underportion
nounEtymology From under- + portion.
1
The lower portion of something; the underneath.
- New relay rooms have been provided at Maidenhead West, Twyford and Reading Main Line East signalboxes; in the latter case an underportion of the building was reconstructed to provide additional rooms for the relay equipment and a diesel standby generator.1962 October, “Talking of trains: New signalbox at Twyford”, in Modern Railways, page 226: