adjective

1. existing as an idea, model, or archetype; consisting of ideas
2. thought of as perfect or as a perfect model; exactly as one would wish; of a perfect kind
3. of, or having the nature of, an idea or conception; identifying or illustrating an idea or conception; conceptual
4. existing only in the mind as an image, fancy, or concept; visionary; imaginary
5. Philos. of idealism; idealistic

Etymology: Fr idéal < LL idealis, existing in idea, ideal < L idea: see idea

noun

1. a conception of something in its most excellent or perfect form
2. a person or thing regarded as fulfilling this conception; perfect model
3. something that exists only in the mind
4. a goal or principle, esp. one of a noble character