Unicode is a standardized character encoding system that assigns a unique number to every character in most written languages. Instead of different regions having different character sets, Unicode provides one global standard.
Specific Unicode blocks are named different, and have a different range. For example:
| Range | Name |
|---|---|
| U+0000 - U+007F | C0 Controls and Basic Latin (Basic Latin) |
| U+0080 - U+00FF | C1 Controls and Latin-1 Supplement (Latin-1 Supplement) |
| U+0100 - U+017F | Latin Extended-A |
| U+0180 - U+024F | Latin Extended-B |
https://unicode-explorer.com/ is helpful for figuring out what character belongs to what unicode block. Latin is the main one for English-like languages (hence, latin), but there are other blocks like Cyrillic, Hebrew, Arabic, etc.
Fonts are often split up between these unicode blocks, which is called subsetting.