D defs.my
Entry 2 senses Webster, 1913

Parenthesis

/(pȧ*rĕn"thē̇*sĭs)/ · Pa·ren·the·sis · IPA /pəˈɹɛnθəsɪs/
01 n. A word, phrase, or sentence, by way of comment or explanation, inserted in, or attached to, a sentence which would be grammatically complet…
pl. Parentheses ((#))
  1. 1.
    A word, phrase, or sentence, by way of comment or explanation, inserted in, or attached to, a sentence which would be grammatically complete without it. It is usually inclosed within curved lines (see def. 2 below), or dashes.
    “Don't suffer every occasional thought to carry you away into a long parenthesis.” — Watts.
  2. 2.
    One of the curved lines () which inclose a parenthetic word or phrase.(Print.)