Three idiom pairs were analysed in order to identify which conceptual motivation, in the form of metaphors, metonymies, embodied motivations and conventional knowledge, were present. Each pair had one Swedish- and one English idiom. They had a similar semantic meaning and they both contained a lexical word for a body part – but not the same body part. The aim was to find out how the idioms could have a similar semantic meaning without having the same structure and the same words. The aim was the research questions were answered by analysing the idiom pairs from a cognitive linguistic perspective. The result of the study showed there are cognitive and conceptual motivations for the underlying process, which makes people understand the idioms in a similar way. The reason for why the Swedish and the English idioms used different words for body parts seems to have been the notion of embodiment and of cultural and conventional knowledge. The different words for the body parts did not seem to affect the semantic similarity of the idiom pair.