sand bar - An area of shallow water which is farther seaward than an area of deeper water (n)

scuba - Lowercase acronym for “self-contained underwater breathing apparatus” (n)

- Leafy, bright green seaweed (n)

sea level - The height of the ocean surface (n)

seaward - In the direction of the ocean (adj)

seaweed - Any of a variety of plant matter found floating in the ocean or bay (n)

set - A collection of waves that are larger than usual (n); two pairs of oars (one for bow and one for stern) (n)

shore break - When the waves break directly onto the beach or very close to the beach (n)

shoulder - The transitional part of the wave, between the white-water and the face (see peeling, curl) (n)

single - A beach with only one guard working that day (n); a beach with one guard at the current time (n)

skeg - The fin that sticks out from the bottom of a surfboard or paddleboard and makes the board go straight (n)

SPF - Sun protection factor (a rating system for sunscreens; an SPF of 15 means 1 hour of exposure while not wearing the sunscreen is the equivalent of 15 hours of exposure while wearing it) (n)

spilling wave - A wave characterized by water falling down the face (n)

stern - The back of the boat (n); near the stern (adj)

stern seat - The seat in the middle of the boat which is closer to the stern (n)

surf - Waves (n); to ride waves using a surfboard (v)

surf line - The farthest point from shore where waves begin to break (n)

surface dive - A dive used by a swimmer to submerge him or herself (n)

surfboard - A fiberglass or epoxy board used for riding waves while standing (n)

surging wave - A wave which may not break until it hits the beach; essentially a swell which never turns into a spilling or plunging wave (n)

swell - An unbroken wave (n)