The word ‘garlic’ originated from the Anglo-Saxon gar-leac or spear plant: from gār ‘spear’ (because the shape of a clove resembles the head of a spear) + lēac ‘leek’. It is closely related to Old Irish gae ‘spear’ and Latin gaesum ‘heavy javlin’, which is often thought to be a Celtic loan. The element -lic is derived from leek with similarities across other Germanic languages (German lauch, Swedish lök, Dutch look). In Swedish, vitlök and Norwegian, hvitløk, the first part of the name means ‘white’; Finnish valkosipuli (valkea ‘white’ + sipuli ‘onion’) follows the same pattern.
Hwæt! We Gár-Dena, in geárdagum, þeódcyninga þrym gefrunon
Lo! We have heard of the renown of the Spear-Danes’ great kings in days of yore
With thanks to polyglotveg; see their blog for a more extensive exploration of garlic’s etymology