pha·lan·gi·um \fəˈlanjēəm, fāˈ-\noun Etymology: New Latin, from Greek phalangion, a spider, from phalang-, phalanx phalanx 1.pluralphalan·gia\-jēə\obsolete: a venomous spider 2.capitalized: a genus (the type of the family the Phalangiidae) of harvestmen