1.
denoting one or more people or things already mentioned or assumed to be common knowledge.
"what's the matter?"
used to refer to a person, place, or thing that is unique.
"the
Queen"
INFORMAL•ARCHAIC
denoting a disease or affliction.
"I've got the flu"
(with a unit of time) the present; the current.
"dish of the day"
INFORMAL
used instead of a possessive to refer to someone with whom the speaker or person addressed is
associated.
"I'm meeting the boss"
used with a surname to refer to a family or married couple.
"the Johnsons were not wealthy"
used before the surname of the chief of a Scottish or Irish clan.
"the O'Donoghue"
2.
used to point forward to a following qualifying or defining clause or phrase.
"the fuss that he made of her"
(chiefly with rulers and family members with the same name) used after a name to qualify it.
"George the Sixth"
3.
used to make a generalized reference to something rather than identifying a particular instance.
"he taught himself to play the violin"
used with a singular noun to indicate that it represents a whole species or class.
"they placed the
African elephant on their endangered list"
used with an adjective to refer to those people who are of the type described.
"the
unemployed"
used with an adjective to refer to something of the class or quality described.
"they are trying to
accomplish the
impossible"
used with the name of a unit to state a rate.
"they can do 120 miles to the gallon"
1. THE cow jumped over me.
2. A cow jumped
over THE moon
3. They’re basically
all the same thing, you just put “the” before a noun
most of the time. (Or else it will be, “You know, kid that used jar of money, took out money, and gave it to family next door.)