a vowel-like sound occurring in consonantal positions in the same syllable with a true vowel, characterized by brief duration and rapid change from one position of articulation to another: the English glides (w) and (y) are semivowels
"semivowel." YourDictionary, n.d. Web. 18 December 2018. <https://www.yourdictionary.com/semivowel>.
semivowel. (n.d.). Retrieved December 18th, 2018, from https://www.yourdictionary.com/semivowel
A sound that has the quality of one of the high vowels, as (ē) or (&oomac;), and that functions as a consonant before or after vowels, as the initial sounds of yell and well and the final sounds of coy and cow. Also called glide .
In the middle of words between vowels f was originally regularly voiced: life, lives; wife, wives, &c. The Latin V, however, was not a labio-dental spirant like the English v, but a bi-labial semivowel like the English w, as is clear from the testimony of Quintilian and of later grammarians.