It's high in trajectory (3)

I believe the answer is:

tor

I'm a little stuck... Click here to teach me more about this clue!

'it's high' is the definition.
I can't tell whether this defines the answer.

'in trajectory' is the wordplay.
'in' indicates a hidden word.
'TOR' can be found hidden inside 'trajectory'.

Can you help me to learn more?

(Other definitions for tor that I've seen before include "(Dartmoor) rocky hill" , "Fermenting agent" , "Rocky prominence" , "Feature of Dartmoor" , "Rot on rocky peak" .)

I've seen this clue in the Evening Standard.

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