n. Among the ancients, originally, a fine yellowish flax, especially Indian and Egyptian, and the linen made from it, such as the Egyptian mummy-cloth; afterward, also, cotton and silk (the latter, before its origin was known, being taken for a kind of cotton).n. One of the byssi, a name formerly given by botanists to a heterogeneous collection of filamentous cryptogamic plants.n. In conchology, a long, delicate, lustrous, and silky bunch of filaments, secreted by the foot, and serving as a means of attachment to other Objects.