'Loosestrife' definitions:

Definition of 'loosestrife'

noun

Any of numerous herbs and subshrubs of the genus Lythrum

noun

Any of various herbs and subshrubs of the genus Lysimachia

From: GCIDE

Loosestrife \Loose"strife`\ (l[=oo]s"str[imac]f`), n. (Bot.) (a) The name of several species of plants of the genus Lysimachia, having small star-shaped flowers, usually of a yellow color. (b) Any species of the genus Lythrum, having purple, or, in some species, crimson flowers. --Gray. [1913 Webster]
False loosestrife, a plant of the genus Ludwigia, which includes several species, most of which are found in the United States.
Tufted loosestrife, the plant Lysimachia thyrsiflora, found in the northern parts of the United States and in Europe. --Gray. [1913 Webster]