From dialectal Arabic جُغْمَة (juḡma), likely a variant of غَمْجَة (ḡamja, “draught, sip”) also of uncertain etymology. Compare Moroccan Arabic جغمة (juḡma)
جغمة • (juḡma) f (plural جغم (juḡam) or جغمات (juḡmāt))