Definitions

1. adjective

Of or relating to the Andes mountain range or its characteristic volcanic rock, typically of intermediate composition between andesite and dacite.

“The andesitic rocks found in the mountain range are a result of volcanic activity.”

2. noun

A type of volcanic rock intermediate in composition between andesite and dacite, typically having a porphyritic texture.

“The geologist collected a sample of andesitic rock from the volcanic region.”