Creating a duration object:

years ( x -- duration )

months ( x -- duration )

weeks ( x -- duration )

days ( x -- duration )

hours ( x -- duration )

minutes ( x -- duration )

seconds ( x -- duration )

milliseconds ( x -- duration )

microseconds ( x -- duration )

nanoseconds ( x -- duration )

instant ( -- duration )

Converting a duration to a number:

duration>years ( duration -- x )

duration>months ( duration -- x )

duration>days ( duration -- x )

duration>hours ( duration -- x )

duration>minutes ( duration -- x )

duration>seconds ( duration -- x )

duration>milliseconds ( duration -- x )

duration>microseconds ( duration -- x )

duration>nanoseconds ( duration -- x )