OC1 - single paddler canoe, OC2, OC3, OC4, OC6 likewise indicating number of seats built in these canoes for paddlers
V1 - Tahitian style outrigger single paddler canoe, rudderless
C1, C2, C4 - single, double, 4 person canoes - this can be Olympic style canoes (paddled kneeling on one knee) or marathon racing canoes w/ exception of the 4 person boat which exists primarily in an Olympic style.
K1, K2, K4 - sprint kayaks
HPK - high performance kayak eg surfski, SK - sea kayak, FSK - fast sea kayak etc. these are designations that were developed to provide some uniformity of boat speed classification for racing - based on width and length of boats. SoundRowers.org Classification Reference
ama - Polynesian term for the outrigger float on the left of an OC or V1
iako - Hawaiian term for a pole (2) that connects amas to their outrigger canoes (Polynesian term is “aka”)
huli - term commonly used by OCers to mean falling in the water which is typically a little more dramatic in an OC because the OCer almost always falls in on their right side with the ama on the left flipping to the right side also. Huli is also becoming more common in usage with other types of boats to also refer to falling in the water.