Highest tree on the street (5)

I believe the answer is:

first

'highest' is the definition.
(thesaurus)

'tree on the street' is the wordplay.
'tree' becomes 'fir' (fir is a kind of tree).
'on' means one lot of letters go next to another.
'the street' becomes 'st' (abbreviation).
'fir'+'st'='FIRST'

(Other definitions for first that I've seen before include "Earliest; good degree" , "Prime" , "Highest degree" , "second to none" , "Foremost" .)

I've seen this clue in The Globe and Mail.

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