keys

metal device shaped in such a way that when it is inserted into the appropriate lock the lock's mechanism can be rotated

something crucial for explaining; "the key to development is economic integration"

any of 24 major or minor diatonic scales that provide the tonal framework for a piece of music

a winged often one-seed indehiscent fruit as of the ash or elm or maple

United States lawyer and poet who wrote a poem after witnessing the British attack on Baltimore during the War of 1812; the poem was later set to music and entitled `The Star-Spangled Banner' (1779-1843)

mechanical device used to wind another device that is driven by a spring (as a clock)

a lever (as in a keyboard) that actuates a mechanism when depressed

identify as in botany or biology, for example

serving as an essential component; "a cardinal rule"; "the central cause of the problem"; "an example that was fundamental to the argument"; "computers are fundamental to modern industrial structure"