What does conditioner mean?
A conditioner is a substance or device that improves the condition of something — most familiarly, a cream or lotion applied to the hair after shampooing to soften it, reduce tangling, and restore moisture lost during washing. Hair conditioners come in many forms, including rinse-out, leave-in, and deep-conditioning treatments, and they are a staple of personal care routines worldwide. The word also appears in compounds: an air conditioner regulates the temperature and humidity of indoor air, while in sports and fitness a conditioner is someone who trains athletes physically. Formed from the verb 'condition' with the agentive suffix '-er', the word literally means 'one who conditions'. In everyday usage, unqualified 'conditioner' nearly always means the hair product, making it one of those household words whose broader literal sense often goes unnoticed.
A substance applied to hair or skin to soften, smooth, and protect it, especially used after shampooing.
"Massage the conditioner into the ends of your hair and rinse thoroughly."
In isolation, this is by far the most common sense of the word.
A device or agent that conditions something, especially an air conditioner that cools and dehumidifies air.
"We finally replaced the ancient air conditioner in the bedroom."
A person who trains others physically to reach a desired level of fitness or performance.
"The team hired a new strength and conditioning specialist as head conditioner for pre-season training."
Regular plural; commonly used when referring to multiple products or units, e.g. different brands of hair conditioner or several air-conditioning units.
"The store stocks dozens of conditioners, from budget basics to salon-only formulas."
The word 'conditioner' didn't start in the salon — it's simply 'one who conditions', which is why your hair product and your air conditioner share a name.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of conditioner
Conditioner derives from the verb 'condition', which entered English in the late Middle Ages from Old French 'condicion', ultimately from Latin 'condicio' meaning agreement or terms, itself from 'condicere', to agree upon. The agentive suffix '-er' turned the verb into a noun meaning 'one who or that which conditions'. The hair-product sense arose in the early twentieth century as commercial hair care developed, and the compound 'air conditioner' became widespread with the growth of mechanical cooling in the same era.
Related word forms
How conditioner is actually used
On its own, 'conditioner' almost always refers to the hair-care product; other senses usually appear as part of a compound such as 'air conditioner' or are clear from context. The word is neutral in register and common in everyday speech on both sides of the Atlantic.
Easily confused with conditioner
Condition is the state of something or a requirement, while conditioner is the agent or product that improves that state.