[ verb ] make tight; secure against leakage
"seal the windows"
Used in print(Francis J. Johnston and John E. Willard, "The...)
Purified inactive chlorine was then added from one of the tubes described above and the mixture frozen_out and sealed_off in a flask equipped with a break_seal .
The desired amounts of inactive chlorine and radioactive chlorine were likewise condensed in these cells on the vacuum line following which they were frozen_down and the manifold as_a_whole was sealed_off .
The reactants for the gas phase experiments were first frozen_out in a side arm attached to the manifold and then allowed to distill slowly into the manifold of pre-cooled reaction cells before sealing_off .