Homonyms
'Bank' has two separate roots
The river bank comes from a Norse word for ridge, the money bank from Italian banca, a moneylender's bench.
More in Homonyms
'Bat' is two unrelated words
Homonyms share spelling and sound but come from different origins. The flying bat and the wooden bat arrived in English separately.
'Lead' is a word with two lives
Spelled the same but pronounced differently, lead the metal and lead the verb are heteronyms, a special kind of homograph.