The rules that use the vocabulary item "zoom" are:
zoom closer in
zoom closer in on <zoomable_thing-gapsout_null-gapsin_null>
zoom farther out
zoom in
zoom in closer
zoom in closer on <zoomable_thing-gapsout_null-gapsin_null>
zoom in on <zoomable_thing-gapsout_null-gapsin_null>
zoom out
zoom out farther