apostrophus

noun

1. The omission of a vowel or syllable from a word, usually indicated by the apostrophe symbol ( ' ). examples: 'til, can't“Vowels suffer also this apostrophus before the consonant h.”
2. The apostrophe symbol used to mark this elision.“The apostrophus or mark of contraction, is the same with the comma, onely the difference is of place; for, this stands not in the line, but over the upper part thereof, where the contraction is:”
3. An open notehead ( ~ ) or an apostrophe ( ' ) used as a neume to mark a low, unaccented syllable at the beginning of a phrase or a short quick syllable“You find not the apostrophus, and so miss the accent. Let me supervise the canzonet.”
4. The symbol 'Ↄ', used in Roman numerals to indicate multiplication by 10.“In every multiplication with ten a fresh apostrophus is added; thus IↃↃ = 5000, IↃↃↃ = 50,000.”