one-to-many
one-to-one
one-touch
one-to-zero
one-track
one-valued
one-way
on-going
onion
onion-layer
  on-line
online
on-line-data
on-link
only
only-under-stress
on-off
on-off-type
onomasiology
onomasticon
on-on

    on-line debugging

    отладка в режиме он-лайн