the.com/red pepper flake

means Dried, crushed red chili pepper (often a blend including cayenne) sprinkled on food for a jolt of heat.

from A straightforward compound: 'red pepper' goes back to the Columbian Exchange, when Europeans encountered chili peppers in the Americas and — confusingly — named them after the unrelated Old World black pepper they were already trading for. 'Flake' simply describes the crushed, papery shape the dried pods take once ground. The now-iconic shaker packets became a pizzeria fixture alongside the parmesan can, likely popularized in the U.S. through Italian-American pizzerias in the 20th century, though the exact 'who started it' is undocumented.