ca·per 2 
(kāpər)
(kāpər)n.
1. A usually spiny Mediterranean shrub (Capparis spinosa) having white to pale lilac flowers and dehiscent fruits with reddish pulp.
2. A pickled flower bud of this plant, used as a pungent condiment in sauces, relishes, and various other dishes.
[Middle English capar, ultimately (probably via back-formation from earlier caperis, caper bush, taken as a plural with the ending -s) from Latin capparis, from Greek kapparis, of unknown origin.]