Pedal is the foot lever on a bicycle or piano, and the verb for pushing it. Petal is the soft, coloured part of a flower. Memory hook: pedal starts with ped-, the Latin root for foot, as in pedestrian.
The core difference
A pedal is something you press with your foot, while a petal is part of a flower.
- pedal — a foot-operated lever, or to work one: She pressed the brake pedal hard when the light turned red.
- petal — one of the leaf-like parts of a flower: Rose petals were scattered across the table.
How to tell them apart
Pedal comes from a Latin word meaning "of the foot", so it always has something to do with feet. Petal is a plant word, so if the sentence is about a flower, rose or blossom, petal is the one you want.
The mix-up shows up because the two words look and sound alike, especially in writing done quickly. Watch for it in phrases like rose petals and bike pedals, where a single wrong letter changes the picture completely.