The translation given by Lane suggests that the word is derived from ↗ǧamal ‘camel’. But this would be a rare pattern. The pl. raises doubts about that, too.
▪ ? Cf. Engl gamma, from Grk gamma, from Phoen *gaml ‘throwstick (?), third letter of the Phoen alphabet’; gimel, from Hbr gîmel ‘gimel’, alteration of Phoen *gaml (see above) - Huehnergard2011.