When used as a noun, a consonant is defined as a sound of speech made by diverting, occluding or obstructing air flowing from the lungs. It is the opposite of a vowel sound. When used as an adjective, consonant means to be in agreement or in harmony.
Examples of a consonant sound made by diverting air flow from the lungs are the sounds for the letters "M" and "N" and the combination "NG." The sounds of consonant letters such as "B," "D," "G," "K," "P" and "T" are made by occluding the air flow, either with or without releasing. The sounds made by obstructing the flow of air include the letters "S," "F," "V" and "Z."