One of meanings of toast is:

a person whose health is drunk.

To me above meaning of toast sounds very weird. How can someone drink one's health? So please help me. By the way why do single english word have so many different meanings?
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Comments  (Page 2) 
I'd say "The toast of the town" is the only way I'd ever heard it used like this (describing the person, not the act of toasting) (or the way you use it above).
Marius HancuIn another direction altogether, one could perhaps say in a very informal way:

His health is toast [SLANG: meaning in very bad shape, finished]

1. n. Any completely inoperable system or component, esp. one that has
just crashed and burned: "Uh, oh ... I think the serial board is
toast." (This sense went mainstream around 1993.)
This use of 'toast' comes from London cockney rhyming slang where 'brown bread' = 'dead' (and toast is brown bread).
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The meaning of "toast" is simple...in mediaeval times in England, the poor of the village would make a strong alcoholic drink (called wassail) and float pieces of toast on top of it. Whoever received a piece of toast in their glass when the drink was poured was considered to be very lucky, and they would drink their toast!
Mister Micawber
a person whose health is drunk.

To me, the question is not "toast", but the phrasing of the definition.
We don't drink a person's health. We drink to a person's health.
But "a person whose health is drunk to" sounds a bit strange!