HYPER'METER, noun [Gr. beyond, and measure.] Anything greater than the ordinary standard of measure. A verse is called a hypermeter when it contains a syllable more than the ordinary measure. When this is the case, the following line begins with a vowel, and the redundant syllable of the former line blends with the first of the following, and they are read as one syllable.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI