General terms:
* Nuance: This is a good general term for a subtle difference in meaning or implication.
* Variation: This emphasizes that the difference is a departure from the usual or standard use.
* Distinction: This highlights the fact that there is a clear, though subtle, difference between the two uses.
More specific terms:
* Register: This refers to the style of language used in a particular situation, such as formal or informal speech. A slight difference in word usage could indicate a change in register.
* Idiom: This describes a phrase or expression that has a meaning that is different from the literal meaning of the words.
* Connotation: This refers to the emotional or cultural associations attached to a word, which can vary depending on the context and the speaker's intended meaning.
Examples:
* "There is a slight nuance in the way the two writers use the word 'love.'"
* "The two dialects of English have a variation in how they pronounce the word 'water.'"
* "There is a clear distinction between using 'happy' and 'content' to describe a person's mood."
* "The use of 'wicked' as a slang term for 'cool' is a register difference."
* "The phrase 'kick the bucket' is an idiom that means 'to die.'"
* "The word 'home' has a connotation of warmth and comfort."
Ultimately, the best term to use will depend on the specific context and the nature of the difference in word usage.