The suffix '-able' or '-ible' in CAPABLE, READABLE, EDIBLE means:

The suffix '-able' or '-ible' means 'able to be' or 'capable of being.' CAPABLE = able to do something; READABLE = able to be read; EDIBLE = able to be eaten. Adding this suffix to a verb often creates an adjective: WASH (verb) → WASHABLE (adjective); BREAK → BREAKABLE; CREDIT → CREDIBLE; PORT → PORTABLE; ACCEPT → ACCEPTABLE. Common suffixes to recognize: -ER/-OR (one who: TEACHER, ACTOR); -IST (one who: ARTIST, BIOLOGIST); -LESS (without: HOPELESS, FEARLESS); -FUL (full of: HOPEFUL, GRATEFUL); -NESS (state of: HAPPINESS, KINDNESS); -MENT (result or process: GOVERNMENT, ACHIEVEMENT); -TION/-SION (action or state: CREATION, DECISION); -LY (in the manner of: QUICKLY, BOLDLY); -OUS (full of: GLORIOUS, FAMOUS); -ABLE/-IBLE (able to be); -IZE/-ISE (to make: MODERNIZE, REALIZE). Suffixes often signal the part of speech, helping you identify the word's grammatical role even when meaning is unfamiliar.