a fragrant shrubby Eurasian plant the leaves of which are used as a cooking herb: Rosmarinus officinalis
There's rosemary, that's for remembrance — Shakespeare
Middle English rosmarine from Latin rosmarinus, from ror-, ros dew + marinus of the sea, perhaps because of its small blue flowers. The change in spelling came about by association with rose1 and the name Mary, either from or giving rise to the legend that the Virgin Mary washed her robe and hung it on a rosemary bush to dry; the dye ran and coloured the flowers