Chilli pepper and Capsicum pepper plant

Chilli pepper noun - Plant bearing very hot and finely tapering long peppers; usually red.

Capsicum pepper plant and chilli pepper are semantically related. In some cases you can use "Capsicum pepper plant" instead a noun phrase "Chilli pepper".

Capsicum pepper plant noun - Any of various tropical plants of the genus Capsicum bearing peppers.

Chilli pepper and capsicum pepper plant are semantically related. Sometimes you can replace phrase "Chilli pepper" with "Capsicum pepper plant", this phrases are similar.