To insert an extra leap day into a calendar in order to maintain synchrony with natural phenomena. / To insert an extra month into a calendar for the same purpose. The Hebrew calendar has such a month.

Describing a time period inserted between others; leap, (as in leap day, leap month, or leap year)

Such a time period

(finance) The total number of contracts outstanding between market participants in a market for futures, options, or other derivatives.

An optical filter in which the wavelengths that are not transmitted are removed by interference rather than by absorption or scattering.

An instrument used to study the differences in the phase of light transmitted through a specimen.

in an interesting way

In Ireland, a tax on interest from savings.

(software design) The structure and definition of the behavior of a system, the surrounding environment, corresponding artifacts, and the elements that communicate the aforementioned behavior.

(computing) A 7-bit character set and character encoding, abbreviated ASCII. Based on the Roman alphabet as used in modern English, the code is employed almost universally on computing machinery.