On

spatial preposition

often translated by sur

• In X is on Y there is contact on at least one side, if Y disappeared, X would fall or disappear.
• Dans la phrase X is on Y, il y a contact d'un côté. Si Y disparassait, X tomberait ou disparaitrait.
  • The book is on the desk.
  • The ornaments are on the tree.
  • The writing is on the wall.

particle

Sometimes translatable with à

Sometimes equivalent to "about" (translatable with à propos de)

Cf. On that special relationship

pre-established circuit marker, with off as its antonym. transmission of energy (turn SO on / turn SO off).

turn on/off

get on/off the bus

on schedule, on time, on target

on the clock, online, on the phone, on TV, on camera, on the air, etc.

turn SO on, lead on, get on with it (a project)

Continuative particle (similar to along)

Move on, lead on, (keep calm and carry on), get on (in age)

evolution

introduced -ing nominals (historically)

is on hunting --> is a-hunting --> is hunting.

Combined with other prepositions

on (the condition) less than --> unless

on till --> until

on --> a (ahead, above, afore, etc.)

Collocations

Light verb + particle

• put STH on = mettre qqch.
• get it on == Cf. Kama Sutra Illustrated, sports, war. it refers to an event as a discourse object
• turn [STH / SO] on == allumer

Prepositional

• get on it == attack a problem, a pile of work, etc. it refers to a discourse object.
• turn on SO = trahir qqn, attaquer un ami