Yesterday, I had the amazing opportunity to take the Fall Spey Casting Class taught by Todd Gerhardt. I also had the surprising opportunity to borrow a spey rod and get on-the-water instruction from Kirby Franklin. The education, coaching and experience was fabulous. While there, I learned a bunch of new fly fishing terms and words like Circle C, Snap T and Double Spey. Learning these new terms inspired the title of this article, which I also got assistance from AI, and I iterated my final edits for a finished glossary.

Fly-fishing can seem like a whole new language when you first start. Between the variety of flies, casting styles, gear, and knowledge of fish habitats, beginners can quickly feel overwhelmed. To help you get started, I've compiled a comprehensive list of terms you’re likely to hear on the water, whether you’re fly casting, spey casting, euro-nymphing, or learning about fish and their environment.

Here is my first attempt at a fly-fishing glossary:

Fly Fishing Basics

Fly Rod – The rod used to cast flies. Comes in various weights, lengths and flexibilities.

Weight of Rod (Rod Weight) – A rating (e.g., 4 wt, 6 wt, 8 wt) indicating the rod’s power and the line weight it is designed to cast.

Flex of Rod – Describes how much the rod bends under load. Fast-action rods bend near the tip, while slow-action rods bend more along the whole rod.

Fly Reel – Holds your fly line and provides drag for fighting fish.

Fly Line – Weighted line used to cast flies. Comes in floating (F), sinking (S), and intermediate (I) types.

Floating Line (F) – A fly line that floats on the water surface. Ideal for dry fly fishing and delicate presentations.

Sinking Line (S) – A fly line that sinks below the water surface, used for nymphs, streamers, or wet flies.

Intermediate Line (I) – Sinks slowly; floats initially but gradually descends. Useful for emergers or shallow nymphing.

Sink Tip Line – A floating line with only the tip section designed to sink, allowing deeper fly presentations while keeping most line on the surface

Weight of Line (Line Weight) – Matched to rod weight for optimal casting (e.g. 2 wt, 3 wt, 4 wt,...9 wt, 10 wt, etc.).

Leader – A tapered line (typically monofilament) attached to the fly line for nearly invisible presentations.

Tippet – The thin section of monofilament line attached to the fly; allows delicate presentations. (i.e. counter intuitively, a 6x tippet has a small diameter; a 2x tippet has a larger diameter).

Backing – Extra line attached to the reel before the fly line; provides extra length when fighting a fish.

Fly – The artificial lure used in fly fishing, mimicking insects, baitfish, or other prey.

Dry Fly – Floats on the water surface, imitating adult insects.

Wet Fly – Sinks below the surface, imitating drowned insects, larvae, or small fish.

Nymph – Underwater, immature stage of aquatic insects; nymph patterns imitate this life stage.

Streamer – Larger fly that imitates baitfish, leeches, or other swimming prey.

Emerger – Represents an insect transitioning from nymph to adult in the water’s subsurface.

Casting Terms

Casting – Delivering the fly to the water.

Fly Casting – Using the rod, line, and leader to present the fly accurately.

Back Cast – Casting the line behind you to build momentum.

Forward Cast – Casting the line forward toward the target.

False Cast – A casting technique where the fly is cast back and forth in the air without touching the water. Used to lengthen the line, adjust distance or direction, or dry a wet fly before the final presentation.

Roll Cast – Casting without a back cast; useful in tight spaces.

Spey Cast – A two-handed casting technique (with longer rods) used in larger rivers or when backcasting room is limited. 

Circle C – A spey-casting curve formed by the line during the initial casting motion; essential for loading the rod efficiently.

Double Spey – A spey-casting variation for long-distance presentations when there is limited room behind the angler, and typically cast across the opposite shoulder.

Snap-T – A sharp motion at the end of a spey cast to load the rod and achieve distance. 

Mend – Adjusting the line on the water to control drift and presentation.

Reach Cast – Casting across the current and placing the line upstream for a natural drift.

Nymphing Terms

Nymphing – A fly-fishing technique where anglers use flies that imitate the underwater nymph stage of insects. Targets fish feeding below the surface at the correct depth. Can be done with tight-line, euro-nymphing, or using a strike indicator. Most effective because fish feed on nymphs year-round.

Tight-Line – Keeping constant contact with the fly for immediate strike detection.

Indicator – A small object (dry fly or bobber) tied on the leader to detect strikes. 

Strike Detection – Recognizing when a fish takes the fly via line movement, rod tip, or indicator.

Weighting – Adding lead or tungsten to flies or split shot to reach the correct depth.

Drift – The natural movement of the fly in the current; a “drag-free drift” mimics natural insect movement.

Euro-Nymphing – A tight-line nymphing style using long leaders and light tippet for subtle strike detection.

Tools, Gear, and Apparel

Nippers – Small clippers for cutting tippet or leader material.

Forceps – Used to remove hooks from fish safely.

Waders – Waterproof clothing that allows anglers to enter the river or stream.

Wading Stick – A staff used to navigate and stabilize in flowing waters. The staff is essential for safety especially in slippery and deep flow conditions.  

Boots – Footwear designed for wading; can have felt soles or rubber for traction.

Felt – Material used for boot soles, providing grip on slippery rocks (note: some areas restrict felt due to invasive species concerns).

Vest / Pack – Holds flies, tools, and accessories for easy access.

Fly Box – Container for organizing and storing flies.

Landing Net – Net used to safely land fish, reducing handling stress.

Strike Indicators – Used to detect subtle bites during nymphing.

Fly Tying Materials & Tools

Hook – The foundation of every fly; used to attach materials and catch fish. Hooks come in a wide range of sizes, from very small (#32) for tiny midges to very large (#2/0 or higher) for big streamers. The size chosen depends on the insect or bait being imitated and the target fish species.

Thread – Used to tie and secure materials to the hook.

Feathers / Hackle – Adds movement and realism to flies.

Fur / Dubbing – Imitates the body of insects or baitfish.

Beads / Eyes – Adds weight and realism to nymphs or streamers.

Wire / Tinsel – For adding flash or durability.

Bobbin – Tool that holds thread and applies tension while tying.

Scissors – Small precision scissors for trimming fly materials.

Bodkin / Needle – Used to manipulate materials or apply head cement.

Whip Finisher – Tool used to finish and secure the knot at the head of the fly.

Head Cement – Glue to ensure the fly stays together and lasts longer.

Common Knots

Improved Clinch Knot – Common for tying tippet to hook.

Surgeon’s Knot – Quick and reliable for joining lines or tippet sections.

Blood Knot – Joins two pieces of tippet of similar diameter.

Nail Knot – Attaches leader to fly line securely.

Fish Life Cycle

Egg – Fertilized eggs are deposited in gravel nests (redds).

Alevin / Sac Fry – Hatchlings still attached to yolk sac, hidden in gravel.

Fry – Newly hatched fish feeding on tiny insects.

Parr – Juvenile fish with vertical markings; feed near the riverbed.

Smolt / Fingerling – Larger juvenile fish beginning migration; may adjust to new water conditions.

Adult / Spawner – Mature fish capable of reproduction; feeding behavior may change seasonally.

Aquatic Insect Life Cycle / Entomology

Egg – Laid on or near water; hatch into nymphs.

Nymph / Larva – Underwater juvenile stage; primary feeding stage.

Pupa – Transition stage between nymph and adult, often near surface.

Emerger – Insect rising from nymph/pupa to adult; important for dry fly fishing.

Adult / Spinner – Fully developed winged insect, mating and laying eggs; targeted by dry flies.

Hatch – Synchronous emergence of insects, triggering intense fish feeding. Common examples: mayflies, caddisflies, stoneflies.

Fish and Ecosystem Terms

Pool – Deep, slow-moving water where fish rest.

Riffle – Shallow, fast-moving water over rocks; oxygen-rich.

Run – Moderately deep section between riffles and pools.

Seam – Where fast and slow currents meet; prime feeding zone.

Cover / Structure – Logs, rocks, undercut banks, or overhanging vegetation providing fish protection.

Holding Water – Areas where fish congregate.

Emergent Insects – Aquatic insects rising to become adults; critical food source.

Benthic Zone – River bottom; home to nymphs and other organisms.

Life Cycle – Understanding insect and fish stages helps select appropriate flies.

Species – Different types of fish, each with unique feeding patterns.

Conservation and Environment Terms

Catch and Release – Returning fish to the water unharmed.

Barbless Hook – a hook with no barb - easier to release fish with minimal impact.

Riparian Zone – Land alongside rivers; important for water quality and fish habitat.

Habitat Restoration – Efforts to improve or repair aquatic environments.

Invasive Species – Non-native organisms that disrupt ecosystems.

Water Temperature – Critical for fish survival and activity.

Flow / Discharge – River volume and speed, affecting insect hatches and fishing conditions.

Sediment – Sand, silt, and clay; excessive amounts harm fish habitats.

Tips for Beginners

1. Learn local hatches and life cycles of insects in your river.
   
   

2. Observe fish behavior to identify seams, pools, and riffles.
   
   

3. Practice casting techniques in an open field.
   
   

4. Handle fish gently and support conservation efforts.
   
   

5. Always wade safely—check depth, currents, and footing before entering water.
   
   

Fly-fishing is as much about understanding nature as it is about technique. Learning these terms will make your time on the water more productive, safer, and enjoyable.