freebase

Short definition from Wiktionary

Noun

1. 1
   The purified, dry form of an amine, especially an alkaloid natural product, that is normally used in solution.
2. 2
   The purified, dry form of certain illegal drugs, especially cocaine.

Verb

1. 1
   To purify a drug by crystallization.
2. 2
   To use a purified drug, especially cocaine, by heating it and inhaling the fumes produced.