'Sea spider' definitions:

Definition of 'sea spider'

From: WordNet
noun
Any of various small spiderlike marine arthropods having small thin bodies and long slender legs [syn: sea spider, pycnogonid]

Definition of 'Sea spider'

From: GCIDE
  • Sea spider \Sea" spi"der\ (Zool.) (a) Any maioid crab; a spider crab. See Maioid, and {Spider crab}, under Spider. (b) Any pycnogonid. [1913 Webster]