I.on [美 ɑn, ɔn, 英 ɒn]介词on often appears as the second element of certain verb structures in English (count on, lay on, sign on, etc). For translations, see the relevant verb entry (count, lay, sign, etc).
For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated glass tube.