Middle English: from the Old French stem round-, from a variant of Latin rotundus 'rotund'
Are round and around (as preposition and adverbial particle) interchangeable in all contexts? In many contexts in British English they are, as in she put her arm round him; she put her arm around him. There is, however, a general preference for round to be used for definite, specific movement (she turned round; a bus came round the corner), while around tends to be used in contexts which are less definite (she wandered around for ages; costing around £3,000) or for abstract uses (a rumour circulating around the cocktail bars).In US English the situation is different. The normal form in most contexts is around; round is generally regarded as informal or non-standard and is only standard in certain fixed expressions, as in all year round and they went round and round in circles.