Sailor crossing lake saw tortoises avoiding the odd bird (9)
I believe the answer is:
albatross
'bird' is the definition.
(albatross is a kind of bird)
'sailor crossing lake saw tortoises avoiding the odd' is the wordplay.
I cannot really understand how this works, but
'sailor' could be 'os' (ordinary seaman) and 'os' is found in the answer.
'lake' could be 'l' (geographical abbreviation) and 'l' is located in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for albatross that I've seen before include "As Borstal is adapted for a big bird" , "Atlas bros alter the large bird with narrow wings" , "can be an encumbrance" , "that golfer with a hole in one might register?" , "Large oceanic bird" .)