(sociolinguistics) A feature, either lexical or phonetical, that is correlated with extralingual factors such as the setting, speaker, addressee etc.

M31-V1: A star, a cepheid variable in Andromeda Galaxy, Local Group, Local Supercluster, Laniakea, located in the Andromeda constellation; the first variable star discovered outside the Milky Way Galaxy, and first star identified whose distance was unequivocably beyond the confines of the Milky Way.

algebraic geometry An algebraic variety equipped a group action of an algebraic torus.