perturb

From Late Middle English perturben (“to disturb (someone) mentally, disquiet; to cause disorder to (something), confuse; to hinder (something)”),^[1] from Old French perturber, and from its etymon Latin perturbāre, the present active infinitive of perturbō (“to confuse; to alarm, disturb, trouble, perturb”), from per- (intensifying prefix) + turbō (“to agitate, disturb, unsettle, perturb; to upset”)^[2] (from turba (“disorder, disturbance, turmoil”) (possibly from Ancient Greek τῠ́ρβη (tŭ́rbē, “confusion, disorder, tumult”), either from Pre-Greek, or Proto-Indo-European *(s)twerH- (“to agitate, stir up; to urge on, propel”)) + -ō (suffix forming infinitives of regular first-conjugation verbs)).

• (Received Pronunciation) IPA^(key): /pəˈtɜːb/
• (General American) IPA^(key): /pəɹˈtɜɹb/

• Audio (General American):

  (file)

• Rhymes: -ɜː(ɹ)b
• Hyphenation: per‧turb

perturb (third-person singular simple present perturbs, present participle perturbing, simple past and past participle perturbed)

1. To disturb; to bother or unsettle.

   Synonyms: agitate, unsettle; see also Thesaurus:upset

2. (physics) To slightly modify the motion of an object.
3. (astronomy) To modify the motion of a body by exerting a gravitational force.
4. (mathematics) To modify slightly, such as an equation or value.

• William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “perturb”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC.
• “perturb”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.
• “perturb”, in OneLook Dictionary Search.

• IPA^(key): [perˈturb]

perturb

1. first-person singular present indicative/subjunctive of perturba