Non-breaking space
An invisible glue space that keeps two neighboring things on the same line, such as an amount and its unit.
See it
What it is
A non-breaking space is a space that renders between two things but forbids a line break there. Its Unicode code point is U+00A0 and its familiar HTML spelling is ' '. It is the tiny piece of glue that keeps a number with its unit, an initial with a surname, or the final two words of a short headline.
Use one when a break would change meaning or leave an ugly fragment: a currency symbol stranded from its amount, '10' separated from 'km', or a one-word runt at the end of a hero heading. For a whole badge, button, or compact UI token that must stay together, CSS 'white-space: nowrap' is clearer than stitching every internal gap with special characters. Some languages require it outright: French typography puts a non-breaking space before the semicolon, colon, exclamation mark, and question mark, and inside guillemets.
The gotcha is that it looks exactly like an ordinary space in most editors. Too many of them create mysterious overflow on narrow screens and make text hard to edit or search. Insert them only at deliberate joins, reveal invisible characters while debugging, and never use a chain of them to fake indentation or layout.
Ask AI for it
Prevent bad line breaks in this responsive card. Insert Unicode U+00A0, written as '\u00A0' in JavaScript or ' ' in HTML, between each number and unit and between the final two words of the short headline. Use CSS 'white-space: nowrap' for the price badge as a whole instead of adding several special spaces. Do not alter ordinary spaces in body copy. Add tests at 320px width and 200 percent zoom that confirm the joined pairs stay together without causing horizontal overflow.