'entertain' originates from Old French, specifically the word 'entretenir', where 'entre-' (from Latin inter-) meant 'among/between' and Latin 'tenere' meant 'to hold'.

'entertain' changed from Old French 'entretenir' into Middle English forms (for example 'enterten') and eventually became the modern English word 'entertain'.

Initially it meant 'to hold among' or 'to keep (someone) in a certain state or condition' (including maintaining or supporting); over time it evolved to the modern primary senses 'to provide amusement or hospitality' and 'to consider (an idea)'.