The difference between Connection and Relation

When used as nouns, connection means the act of connecting, whereas relation means the manner in which two things may be associated.

check bellow for the other definitions of Connection and Relation

Connection as a noun (uncountable):

The act of connecting.
Connection as a noun:

The point at which two or more things are connected.

Examples:

"the connection between overeating and obesity"

"My headache has no connection with me going out last night."
Connection as a noun:

A feeling of understanding and ease of communication between two or more people.

Examples:

"As we were the only people in the room to laugh at the joke, I felt a connection between us."
Connection as a noun:

An established communications or transportation link.

Examples:

"computers linked by a network connection"

"I was talking to him, but there was lightning and we lost the connection."
Connection as a noun (transport):

A from one transportation vehicle to another in scheduled transportation service

Examples:

"The bus was late so he missed his connection at Penn Station and had to wait six hours for the next train."
Connection as a noun:

A kinship relationship between people.
Connection as a noun:

An individual who is related to oneself.

Examples:

"I have some connections in Lancashire."
Connection as a noun:

A of sets that contains the empty set, all one-element sets for any element that is included in any of the sets, and the of any group of sets that are elements where the intersections of those sets is non-empty.
Connection as a noun:

; lack of disjointedness

Relation as a noun:

The manner in which two things may be associated.

Examples:

"The relation between diet and health is complex."
Relation as a noun:

A member of one's family.

Examples:

"Yes, he's a relation of mine, but only a distant one."
Relation as a noun:

The act of relating a story.

Examples:

"Your relation of the events is different from mine."
Relation as a noun (set theory):

A set of ordered tuples.
Relation as a noun (set theory):

Specifically, a set of ordered pairs.

Examples:

"Equality is a symmetric relation, while divisibility is not."
Relation as a noun (databases):

A set of ordered tuples retrievable by a relational database; a table.

Examples:

"This relation uses the customer's social security number as a key."
Relation as a noun (mathematics):

A statement of equality of two products of generators, used in the presentation of a group.
Relation as a noun (category theory):

A subobject of a product of objects.
Relation as a noun (usually collocated: sexual relation):

The act of intercourse.