'thyroid-stimulating' originates from Modern English, formed from 'thyroid' (from New Latin 'thyreoideus') and 'stimulating' (from Latin 'stimulare'), where 'thyreos' meant 'shield' and 'stimul-' meant 'goad' or 'incite'.

'thyroid' changed from Greek 'thyreoeidēs' to New Latin 'thyreoideus' and entered English as 'thyroid' (referring to the shield-shaped gland); 'stimulate' came from Latin 'stimulare' via Old French/Middle English into modern English 'stimulate', and the compound adjective 'thyroid-stimulating' was formed in modern medical English to describe agents that stimulate the thyroid.

Initially 'thyroid' referred to the gland's shield-like shape and 'stimulate' meant 'to goad or incite'; over time the combined phrase evolved to mean 'causing stimulation of the thyroid gland' in physiological and medical contexts.