* Basic: fundamental, essential, or primary.
* Basilica: a large, rectangular building, typically with a nave, aisles, and apse, used as a Christian church.
* Basidiomycete: a type of fungus that produces spores on a basidium.
* Basilar: relating to the base or bottom part of something, especially the skull.
* Basion: a point on the skull at the center of the foramen magnum, the opening at the base of the skull.
* Basify: to make something basic or alkaline.
* Basipetal: moving or directed toward the base of something.
* Basitonic: relating to a type of igneous rock that has a high percentage of silica.
* Basilic: relating to a basilisk, a mythical serpent said to be able to kill with its breath.
The prefix "basi-" comes from the Greek word "basis," meaning "base" or "foundation." It typically indicates something that is fundamental, foundational, or located at the base of something.