When is a word a word and when is it two words, or even three? A strange thing about English is its ability to assimilate different words into the same form.
There are two words with the same spelling. One of these words has two pronunciations but its meanings all relate to the idea of bending.
It is the thing used to shoot an arrow. It is a knot made with two loops, typically used to tie shoelaces or worn by girls in their hair or in a bow tie. The elbow is the joint where the arm bends in the middle.
The ﬁrst is the verb related to the noun described above. It means to bend forward from the waist as a mark of respect. To bow your head is to let it fall forward as a sign of humility or shame. To be bowed down with care is to be oppressed by it. To take a bow is to recognise applause or congratulation, literally or metaphorically.
The other word is the rounded or pointed part at the front of a ship. Another form of this second word, bough (with the same pronunciation), is a poetical word for the branch of a tree. Most native speakers are not aware that these words have different origins.
The word case represents two separate words that have no etymological connection.
A case is a container that is speciﬁcally designed to contain one particular item: cigarette case, glasses case, pen/pencil case. A suitcase is used for carrying clothes. A briefcase is a container used for carrying papers; the reference is to the use of the word brief to refer to the notes that a barrister uses.
Lower case and upper case letters are other names for small letters and capital letters respectively. Printers used to keep the small letters in the lower part of the case in which they kept their type and the capital letters in the upper part of it.
From a different origin, it means an example or occurrence of something: An interesting case. A case of meningitis and is used as a grammatical term
A case meaning a container, a suitcase for example, or upper- and lower-case letters, has a different origin from a case as an example, phenomenon, a case of malaria or the nominative case.
Then suffix -most, found in topmost, northernmost, and similar words, is not the same as the superlative adverb in most difficult.
This means to hit with a closed ﬁst; it can be used as a noun (throw a punch). It also means to make a hole in paper, metal, leather etc. and is the name of the tool used for doing so. You can punch a piece of metal or punch a hole in a piece of metal.
A policy /"pQlIsi/ is the course of action or strategy adopted by a government, company, other organisation, or an individual. A document stating the terms and conditions of an insurance contract is also called a policy.
These are different words. As a course of action it is related to polite and police. The word policy as used in insurance terms is from French, and probably ultimately from Greek apodeixis meaning evidence, proof.
A pool is a small body of water occurring naturally. Pools suitable for swimming in are called swimming pools, but now swimming pools are usually artiﬁcial.
A pool is also the result of people contributing money or other resources to a common fund. Businesses may pool their capital; friends on holiday together may pay money into a pool for food and other common expenses. The pools (usually plural) is a system of betting on football matches where the money paid is pooled and distributed to the winner or winners; this idea also lies behind the name of the game pool, which is similar to billiards and snooker.
Some companies and other large organisations have a car pool where cars are provided in common for employees, a group of friends or neighbours might organise a car pool to take each other’s children to school, and journalists in difﬁcult conditions might form a pool to exchange information that they have gathered.
Although these two words (pool of water and common resources) have different origins, they are associated in the minds of many people.
All of the above deﬁnitions derive ultimately meaning a gate. The person responsible for guarding the gate of a town or building derives from the Latin porta. However, a different origin (Latin portare) gives the word porter as someone who carries things, especially luggage at railway stations and airports.
Found (create, originate), founder (sink) and foundry (a place where metal is worked) are all different in origin.
This is based on articles in my A Guide to English Language Usage from Lavengro Books.