'tentacle' originates from Modern Latin, specifically the word 'tentaculum', where the root 'tent-' (from Latin 'tentare') meant 'to feel' or 'to try'.

'tentacle' changed from the French/Latin form 'tentacule'/'tentaculum' in early modern usage and eventually became the modern English word 'tentacle' in the 17th century.

Initially, it meant 'a feeler or sensing appendage', but over time it evolved into its current meanings including both the biological 'flexible limb' and the figurative sense of an organization's 'reach' or 'influence'.