The difference between Lower and Shorten

When used as verbs, lower means to let descend by its own weight, as something suspended, whereas shorten means to make shorter.

check bellow for the other definitions of Lower and Shorten

Lower as an adjective:
Lower as an adjective:

bottom; more towards the bottom than the middle of an object
Lower as an adjective (geology, of strata or geological time periods):

older

Lower as a verb (transitive):

To let descend by its own weight, as something suspended; to let down

Examples:

"lower a bucket into a well"

"to lower a sail of a boat"
Lower as a verb (transitive):

to pull down

Examples:

"to lower a flag"
Lower as a verb (transitive):

To reduce the height of

Examples:

"lower a fence or wall"

"lower a chimney or turret"
Lower as a verb (transitive):

To depress as to direction

Examples:

"lower the aim of a gun"
Lower as a verb (transitive):

To make less elevated

Examples:

"to lower one's ambition, aspirations, or hopes"
Lower as a verb (transitive):

To reduce the degree, intensity, strength, etc., of

Examples:

"lower the temperature"

"lower one's vitality"

"lower distilled liquors"
Lower as a verb (transitive):

To bring down; to humble

Examples:

"lower one's pride"
Lower as a verb (reflexive):

(lower oneself) To humble oneself; to do something one considers to be beneath one's dignity.

Examples:

"I could never lower myself enough to buy second-hand clothes."
Lower as a verb (transitive):

To reduce (something) in value, amount, etc.

Examples:

"lower the price of goods"

"lower the interest rate"
Lower as a verb (intransitive):

To fall; to sink; to grow less; to diminish; to decrease

Examples:

"The river lowered as rapidly as it rose."
Lower as a verb (intransitive):

To decrease in value, amount, etc.

Shorten as a verb (transitive):

To make shorter; to abbreviate.
Shorten as a verb (intransitive):

To become shorter.
Shorten as a verb (transitive):

To make deficient (as to); to deprive (of).
Shorten as a verb (transitive):

To make short or friable, as pastry, with butter, lard, etc.
Shorten as a verb (transitive):

To reduce or diminish in amount, quantity, or extent; to lessen.

Examples:

"to shorten an allowance of food"
Shorten as a verb (nautical, transitive):

To take in the slack of (a rope).
Shorten as a verb (nautical, transitive):

To reduce (sail) by taking it in.