TASK DEFINITION: Generate the answer for a given question. The question requires common knowledge of English. Make sure that the answer is in detail, long, consistent with the context, and requires general knowledge of English. To be less repetitive, please vary your language for each question. Give a proper explanation to answer, and if necessary, provide the definition of various terms. And conclude your answer if it's long. If you have used other resources (e.g., Merriam Webster's.) to answer the question, include citations in your answer. You don't need to paraphrase the context of your resources, but make sure that your answer is consistent and complete.
PROBLEM: Is there a way to indicate that somebody is your girlfriend without using the possessive term my? I think saying She/He is my partner/other half is OK for married people, but it doesn't feel right for girlfriends and boyfriends.

SOLUTION: There is nothing wrong with using my. Saying my medical appointment does not mean the medical appointment belongs to me, but just that it is connected to me in some way. Stick to my for there is no alternative which expresses the idea succinctly.

PROBLEM: Are Backronym and Acronym same? I don't understand the difference between these two terms.

SOLUTION: An acronym is a word formed by the initial letters of other words, such as Nato (North Atlantic Treaty Organisation). Note that this is different to an initialism where the initial letters are spelled out, as in BBC for example. A backronym is where the word comes first, and the initial letters are made to fit the word. An example is Alex the parrot (Wikipedia) who to date is the only non-human to spontaneously use language and throws doubt on the notion that a large brain is a prerequisite for language. The name Alex was subsequently said to be 'Avian Language Experiment', which then became 'Avian Learning Experiment. As this was decided (or at least stated) after naming the bird, it is a backronym. Another example would be the USA PATRIOT Act, where : The title of the act is a ten-letter backronym (USA PATRIOT) that stands for Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (Wikipedia)

PROBLEM: These two seem very similar. What are the major differences between the two? For example, in the following sentence, Substitute the lesser punishment for the greater one. Can one use 'less' instead of 'lesser' here?.

SOLUTION:
Less refers to quantity, lesser refers to quality. Your sentence could be rephrased as 'substitute less punishment for more punishment.' Here we are saying that the amount of punishment is smaller. But if you say 'substitute the lesser punishment' you are saying the type of punishment is not as severe. Forty lashes is less punishment than 100 lashes. Being pelted with rotten tomatoes is a lesser punishment than being pelted with rocks.