1. A change in the form of a word, especially the addition, omission, or transposition of letters or syllables.
Usage: linguistics; formal
2. In ancient rhetoric, a figure of speech involving the alteration of a word's form for metrical or stylistic effect.
Usage: archaic; classical rhetoric

Examples

• The word 'ask' underwent metaplasm when it became 'aks' in some dialects.
• Linguists study metaplasm to understand how languages evolve over time.
• The shift from 'Old English' to 'Modern English' involved numerous instances of metaplasm.
• In poetry, metaplasm was sometimes used to fit words into a required metrical pattern.
• The addition of a prefix to a root word is one type of metaplasm.