What is the meaning of Blackberry?

A fruit-bearing shrub of the aggregate species Rubus fruticosus and some hybrids.

The soft fruit borne by this shrub, formed of a black (when ripe) cluster of drupelets.

Any Rubus berry that is black or blackish; the plant that produces it.

The blackcurrant.

To gather or forage for blackberries.

Source: wiktionary.org