A prefix denoting under, below, low; e.g. hypotonic.
Biology
A prefix denoting under, below, low; e.g. hypogyny, hyponasty.
Geology and Earth Sciences
From the Greek hupo meaning ‘under’, a prefix meaning ‘below’, ‘slightly’, or ‘lower than normal’. ‘Hypo-’ is generally used before words beginning with a consonant, ‘hyp-’ before words beginning with a vowel.