'atomize' (and thus 'atomizing') originates from Modern French 'atomiser' and New Latin 'atomizare', ultimately from Greek 'atomos', where 'a-' meant 'not' and 'temnein' meant 'to cut'.

'atomos' (Greek 'indivisible') passed into Late Latin/Medieval Latin and New Latin as 'atomus'/'atomizare', then into French as 'atomiser' and entered English as 'atomize' in the 17th century; the -ing form 'atomizing' is the present participle/gerund derived from English 'atomize'.

Initially related to the idea of 'indivisible' (Greek 'atomos'), the sense evolved into 'to reduce to atoms' or 'to separate into very small parts'; in modern use it additionally includes 'to spray into fine droplets' and figurative senses of 'break down into components'.