Illustrated Glossary of Organic Chemistry

Primary alkyl halide (1o alkyl halide; primary haloalkane; 1o haloalkane): An alkyl halide (haloalkane) in which the halogen atom (F, Cl, Br, or I) is bonded to a primary carbon.

General primary alkyl halide structure.
Z = any halogen atom (F, Cl, Br, or I).
X = any atom but carbon (usually hydrogen).