Meaning

noun the series of vertebrae forming the axis of the skeleton and protecting the spinal cord

noun any sharply pointed projection

noun a small sharp-pointed tip resembling a spike on a stem or leaf

originFrom late Middle English spyne, from Old French espine (French épine) or its source, Latin spīna (“a thorn; a prickle, spine; the backbone”). Doublet of spina.

Etymology from Wiktionary, CC BY-SA 3.0