Wats a Carrier ?

What does the word “carrier” indicate ?
I used to think that I had a fairly good idea of English Language. But nothing prepared me for the different meanings a simple word can construe.
A colleague and me were walking from an evening dose of ‘chai’.
That was a time period when people of another company were leaving from their morning shift.
As we were walking, my colleague mentioned “ So many carriers in this building?”
For a split second I did not really get it as to what was the main subject.
For me, carrier implied a vessel or more like the ‘dabba’ you get as your lunch box.
Or somebody sitting on the pillion carrier of a two wheeler. But as far as I could see there were just lots of people walking down to the gate.
I know that wiki has lots of meanings for carrier.
But I was seriously stumped that what could possibly be this ‘carrier’.
Then realization dawned and what she was referring was that there are lots of pregnant ladies or rather expectant mothers among the lot who had left for the day.
Too much I say …
Ciao,
Tina :)