Crossword Genius

Sauce, month old (4)

Ross

I believe the answer is:

mayo

'sauce' is the definition.

'month old' is the wordplay.
'month' becomes 'may' (May is an example**).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'may'+'o'='MAYO'

(Other definitions for mayo that I've seen before include "part of Ireland" , "Saucy thing" , "Irish county; dressing" , "Cold, creamy sauce (abbr)" , "Eg, Braeburn or Cox" .)

I've seen this clue in The Times.
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