Many, if not all, languages have homonyms (омонимы) – words that look and sound the same but have different meanings. Think of 'bow' or 'cool' in English, they too have more than one meaning. Russian is no exception. It might make things confusing even for someone advanced in the language, when you see a word like ручка and don't know if this time it means a handle or a pen. I'll give you some examples of Russian homonyms.
лук — onion; bow (weapon)
ручка — handle; pen
коса — scythe; braid; spit (landform)
косой — cross-eyed; askew, sideways; nickname for a hare
бабочка — butterfly; bow-tie
брак — marriage; spoilage, flaw (in a product)
мир — peace; world; society («Война и мир» - “War and peace” can also be translated from Russian as 'War and society' and 'War and world')
киви — kiwi fruit; kiwi bird
мука — torture (мука — first syllable is stressed); flour (мука — second syllable is stressed)
чайник — teapot, kettle; inexperienced driver, a beginner in general, a dummy (colloquial word).