Definition of "narrowing"

Owing to the war, it was not thought advisable to carry out repairs to this pier, as this would have involved the temporary narrowing of the channel, and it was not until 1919 that it was decided to proceed with the construction of a steel-pile coffer dam round the south pier.

1949 November and December, “Notes and News: The High Level Bridge, Newcastle: Strengthening and Repairs”, in Railway Magazine, page 407

It may be observed, as a general rule, that the length of a stocking, before the narrowings, should be, at the least, equal to twice the width of the top...

1858, Margaret Maria Gordon, Household economy, page 60