Organic vocabulary

Commonly used terms in Organic Chemistry

 Alkyl group: A collection of singly bonded carbons and hydrogens which has one unfulfilled valency at carbon. These may be represented by R in the general formula for a compound.
Substituent: An atom or group of atoms replacing hydrogen.  Alkyl groups may be substituents on a carbon chain.

Double bond equivalents (Degrees of unsaturation): 
This is the sum the total number of π (pi) bonds and rings in a compound.
A double bond has one π bond. A triple bond has two π bonds.

Primary, Secondary and Tertiary

Alcohols (ROH)  Alkyl halides (RX)	If C bearing OH (or X) is also bonded to one carbon - primary (1°) two carbons - secondary (2°) three carbons - tertiary (3°)
Amines (R3N)	If N is bonded to one carbon - primary (1°) two carbons - secondary (2°) three carbons - tertiary (3°)