In obsolete|lang=en terms the difference between aback and backward

is that aback is (obsolete) an abacus while backward is (obsolete) already past or gone; bygone.

As adverbs the difference between aback and backward

is that aback is (archaic) towards the back or rear; backwards while backward is (of motion) in the direction towards the back; backwards.

As nouns the difference between aback and backward

is that aback is (obsolete) an abacus while backward is the state behind or past.

As an adjective backward is

(of motion) pertaining to the direction towards the back.

As nouns the difference between foam and caramel

is that foam is a substance composed of a large collection of bubbles or their solidified remains while caramel is a smooth, chewy, sticky confection made by heating sugar and other ingredients until the sugars polymerize and become sticky.

As a verb foam

is to form or emit foam.

As an adjective foamy

is full of foam.

As a noun caramel is

a smooth, chewy, sticky confection made by heating sugar and other ingredients until the sugars polymerize and become sticky.

As an adjective frothy

is foamy or churned to the point of becoming infused with bubbles.

As a noun caramel is

a smooth, chewy, sticky confection made by heating sugar and other ingredients until the sugars polymerize and become sticky.

As nouns the difference between sign and whistle

is that sign is (sometimes|also used uncountably) a visible indication while whistle is a device designed to be placed in the mouth in order, or driven by steam or otherwise, to make a whistling sound.

As verbs the difference between sign and whistle

is that sign is to make a mark while whistle is (ambitransitive) to make a shrill, high-pitched sound by forcing air through the mouth to produce a whistling sound, restrictions to the flow of air are created using the teeth, tongue and lips.

In transitive terms the difference between argue and defend

is that argue is to present (a viewpoint or an argument therefor) while defend is to support by words or writing; to vindicate, talk in favour of.

As verbs the difference between argue and defend

is that argue is to prove while defend is to ward off, repel (an attack or attacker).

As nouns the difference between packrat and collector

is that packrat is any of several species of rodent in the genus ) while collector is a person who or thing which collects, or which creates or manages a collection.

Indenturedservant is likely misspelled.

Indenturedservant has no English definition.

As a noun bondservant is

an indentured servant.

As nouns the difference between decorum and cordial

is that decorum is decorum while cordial is (uk|au|nz) a concentrated noncarbonated soft drink which is diluted with water before drinking.

As an adjective cordial is

hearty; sincere; warm; affectionate.

As adjectives the difference between realistic and physical

is that realistic is expressed or represented as being accurate while physical is having to do with the body.

As a noun physical is

physical examination.