alkyl groups

Univalent groups derived from alkanes by removal of a hydrogen atom from any carbon atom –CnH2n+1. The groups derived by removal of a hydrogen atom from a terminal carbon atom of unbranched alkanes form a subclass of normal alkyl (n-alkyl) groups H(CH2)n. The groups RCH2, R2CH (RH), and R3C (RH) are primary, secondary and tertiary alkyl groups, respectively.
See also: cycloalkyl groups, hydrocarbyl groups
PAC, 1995, 67, 1307 (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1314