A syllable ending in a vowel is said to be open; one ending in a consonant is closed. Thus, in μή-τηρ mother the first syllable is open, the second closed.
Topic · from the English index · as printed
Open
syllable
§141SYLLABLES AND THEIR QUANTITY
vowels, the
§4 aVowels and Diphthongs
There are seven vowels: α, ε, η, ι, ο, υ, ω. Of these ε and ο are always short, and take about half the time to pronounce as η and ω, which are always long; α, ι, υ are short in some syllables, long in others. In this Grammar, when α, ι, υ are not marked as long (ᾱ, ῑ, ῡ) they are understood to be short. All vowels with the circumflex (149) are long. On length by position, see 144.
a. Vowels are said to be open or close according as the mouth is more open or less open in pronouncing them, the tongue and lips assuming different positions in the case of each.