breast
The Italian word 'seno' is used to refer to the breast, both in a medical context and in general conversation. It is a noun and is used in the same way as the English word 'breast'. For example, 'Il seno sinistro è più grande del destro' means 'The left breast is larger than the right one'.
My left breast hurts.
This sentence might be used to express personal discomfort or pain in the chest area. 'Seno' in this context refers to the chest or breast.
The sine of this function is always positive.
In a mathematical context, 'seno' is used to refer to the sine of a function, a concept in trigonometry.
The inlet of this bay is very peaceful.
In a geographic context, 'seno' can refer to an inlet, a narrow body of water between islands or leading inland from a larger body of water.