The difference between Auto and Manual

When used as nouns, auto means an automobile, whereas manual means a handbook.

When used as adjectives, auto means automatic, whereas manual means performed with the hands (of an activity).

check bellow for the other definitions of Auto and Manual

Auto as an adjective:

automatic

Examples:

"It's an auto sedan which we picked up from a wholesaler locally."

Auto as a noun (chiefly, [[attributive]]ly):

An automobile.

Examples:

"My brother is an auto mechanic."
Auto as a noun:

A setting for automatic operation.

Examples:

"Put it on auto."
Auto as a noun:

A writ.
Auto as a noun:

An automatic gearbox / transmission.

Examples:

"A body coloured centre pillar signalled the arrival of an electronic four-speed auto, slight suspension revisions and minor trim changes."
Auto as a noun:

A car with an automatic gearbox / transmission.

Examples:

"It wasn't too bad but we did hire an auto (couldn't imagine changing gears with my right hand)."

Auto as a noun (India):

An autorickshaw.

Examples:

"... users are often unable to note down the number of the taxi or the auto as the driver will just zoom past."

Manual as a noun:

A handbook.
Manual as a noun:

A booklet that instructs on the usage of a particular machine or product.

Examples:

"The dishwasher isn't working; can you remember where we put the manual?"
Manual as a noun (military):

A drill in the use of weapons, etc.
Manual as a noun (Christianity, historical):

An old office-book like the modern Roman Catholic ritual.
Manual as a noun (music):

A keyboard for the hands on a harpsichord, organ, or other musical instrument.
Manual as a noun:

A manual transmission; a gearbox, especially of a motorized vehicle, shifted by the operator.
Manual as a noun (by synecdoche):

A vehicle with a manual transmission.
Manual as a noun:

A bicycle technique whereby the front wheel is held aloft by the rider, without the use of pedal force.
Manual as a noun (medicine, colloquial):

Manual measurement of the blood pressure, done with a manual sphygmomanometer.

Examples:

"do a manual"

Manual as an adjective:

Performed with the hands (of an activity).
Manual as an adjective:

Operated by means of the hands (of a machine, device etc.).
Manual as an adjective (technology):

Performed by a human rather than a machine.

Examples:

"The student manually corrected several errors missed by the [[spell checker]]."