‖n.; pl.Aciculæ [ L., a small needle, dimin. of acus needle. ] (Nat. Hist.) One of the needlelike or bristlelike spines or prickles of some animals and plants; also, a needlelike crystal. [ 1913 Webster ]
{ a. (Nat. Hist.) (a) Furnished with aciculæ. (b)Acicular. (c) Marked with fine irregular streaks as if scratched by a needle. Lindley. [ 1913 Webster ]