The difference between Finger and Rat out

Finger as a noun (anatomy):

A slender jointed extremity of the human hand, exclusive of the thumb.

Finger as a noun (zoology):

Similar or similar-looking extremities in other animals, particularly: The lower, smaller segment of an arthropod claw. One of the supporting structures of wings in birds, bats, etc. evolved from earlier toes or fingers. One of the slender bony structures before the pectoral fins of gurnards and (Triglidae).

Finger as a noun (cuisine):

Something similar in shape to the human finger, particularly: Finger-shaped pieces of food. A tube extending from a sealed system, or sometimes into one in the case of a cold finger. (D. purpurea).

Finger as a noun (especially):

Something similarly extending, from a larger body, particularly: Various protruding plant structures, as a banana from its hand. A lobe of the liver. The teeth parallel to the blade of a scythe, fitted to a wooden frame called a crade. The projections of a reaper or mower which similarly separate the stalks for cutting. : a shorter, narrower pier projecting from a larger dock. : the narrow elevated walkway connecting a plane to an airport.

Finger as a noun (usually):

Something similar in function or agency to the human finger, with regard to touching, grasping, or pointing. , the part of a clock pointing to the hour, minute, or second. A policeman or prison guard. An informer to the police, one who identifies a criminal during a lineup. A criminal who scouts for prospective victims and targets or who performs reconnaissance before a crime. That which points; an indicator, as of guilt, blame, or suspicion.

Finger as a noun (units of measure):

Various units of measure based or notionally based on the adult human finger, particularly : former units of measure notionally based on its width but variously standardized, the English digit of foot (about 1.9cm). A unit of length notionally based on the length of an adult human's middle finger, standardized as 4½inches (11.43cm). : the observed diameter of the sun or moon, with regard to eclipses. An informal measure of alcohol based on its height in a given glass compared to the width of the pourer's fingers while holding it.

Finger as a noun (fashion):

A part of a glove intended to cover a finger.

Finger as a noun (informal, obsolete):

Skill in the use of the fingers, as in playing upon a musical instrument.

Finger as a noun (informal, rare):

Someone skilled in the use of their fingers, a pickpocket.

Finger as a noun (UK, _, slang):

A person.

Finger as a noun:

A .

Finger as a noun (especially in the phrase 'give someone the finger'):

An obscene or insulting gesture made by raising one's middle finger towards someone with the palm of one's hand facing inwards.

Finger as a verb (transitive):

To identify or point out. Also put the finger on. To report to or identify for the authorities, rat on, rat out, squeal on, tattle on, turn in, to finger.

Finger as a verb (transitive):

To poke or probe with a finger or fingers.

Finger as a verb (transitive):

To use the fingers to penetrate and sexually stimulate one's own or another person's vagina or anus; to fingerbang

Finger as a verb (transitive, music):

To use specified finger positions in producing notes on a musical instrument.

Finger as a verb (transitive, music):

To provide instructions in written music as to which fingers are to be used to produce particular notes or passages.

Finger as a verb (transitive, computing):

To query (a user's status) using the .

Finger as a verb (obsolete):

To steal; to purloin.

Finger as a verb (transitive, obsolete):

To execute, as any delicate work.

Rat out as a verb (slang, derogatory, transitive):

To inform authorities (about someone); to tell on (somebody).