\bigstrut produces a strut which is \bigstrutjot higher, lower, or both, than the standard array/table strut. Use it in table entries that are adjacent to an \hline, to leave an extra bit of space.

Note that the tabls package does the job automatically, and the booktabs package has a completely different mechanism for dealing with the problem, which obviates the need for manual adjustment.

See also multirow tabls.

The author is Piet van Oostrum.