IPA: /ˌhaɪpəˈtɒnɪk/
KK: /haɪpəˈtɒnɪk/
Describing a solution that has a lower concentration of solutes compared to another solution, often leading to a lower osmotic pressure.
The hypotonic solution caused the cells to swell as water moved in.
Hypotonic is formed from "hypo-" (meaning under or below) and "tonic" (from Greek "tonikos", meaning tension or tone). The word describes a solution that has a lower concentration of solutes compared to another solution, thus having less tension or tone in terms of osmotic pressure.
Think of 'hypo-' meaning 'under' or 'below' and 'tonic' relating to 'tension' — this helps you remember that hypotonic refers to a solution with less tension or concentration.