1.nounA sound that results from the passage of air through restrictions of the oral cavity; any sound that is not the dominant sound of a syllable, the dominant sound generally being a vowel.
2.nounA letter representing the sound of a consonant.
"The 19 unquestionable consonants in the English alphabet are B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, X, Z."