An odometer is a device that is used for measuring how far you have traveled. Odometers are usually fitted inside cars and other vehicles.
Of is a word that can indicate distance, source or reason. Some examples are: "I live south of the intersection" "a slice of cake" "that dress is made of polyester".
Something is off if it is not powered up and available to be used. The computer in the picture is switched off. Off also can be used to indicate something no longer attached to something else: "the branch broke off the tree", or for reducing something: "take ten percent off the price". The opposite of off is on.
An office is a room, a group of rooms or even an entire building where professionals work. Offices are usually full of desks and computers.
Offshore means in the water some distance from the shore, the sandy area where land meets a body of water such as an ocean or a lake.
Oil is a substance that is liquid at room temperature. Oil does not mix with water. Oil can be heated to much higher temperatures than water can, and so is useful in cooking food. Because oil does not stick to things, it is used to help stop food sticking when it is being cooked, and it helps stop parts of machinery like car engines from sticking together when they are running. Most oils will burn under the right conditions and can be used as a heat or light source, and a fuel to run things like internal combustion engines. Oil can be made from the seeds of many plants, as well as dug up from under the ground. Oil that comes from the ground used to be plants or animals many thousands of years ago, and had been changed into oil by the movement of the Earth.
OK or okay means everything is all right and good. OK is short for the slang "all correct", or orl korrect.
Something is old if it has existed for a very long time. Something that is really, really old is called ancient. When people get old they get grey hair and wrinkles.
The Old English Sheepdog is a very old breed of large herding dog. It has very long, thick, grey-and-white hair all over it, covering its face. Old English sheepdog puppies are born black-and-white. They are friendly, sociable dogs. They are high maintainence though, as their coat needs regular brushing and clipping.
Something is old fashioned if it looks like it belongs in the past, and doesn't fit in with things around it. Clothes can be old fashioned, and behaviour can be old fashioned too. Old fashioned things can also be called retro.