Encountered engineers in the distance (5)
I believe the answer is:
metre
'distance' is the definition.
(unit of distance)
'encountered engineers' is the wordplay.
'encountered' becomes 'met' ('meet' can be a synonym of 'encounter').
'engineers' becomes 're' (Royal Engineers).
'met'+'re'='METRE'
'in the' is the link.
(Other definitions for metre that I've seen before include "39.37 inches" , "determined by scanning" , "measure of length" , "Beat pattern (mus.)" , "Approximately 39 inches" .)