| Noun | 1. | leaflet - a thin triangular flap of a heart valveflap - a movable piece of tissue partly connected to the body | |
| 2. | leaflet - part of a compound leaffoliage, leaf, leafage - the main organ of photosynthesis and transpiration in higher plants pinna, pinnule - division of a usually pinnately divided leaf | |
| 3. | leaflet - a small book usually having a paper coverbook - a written work or composition that has been published (printed on pages bound together); "I am reading a good book on economics" blue book - a blue-covered booklet used in universities for writing examinations ticket book - a book of tickets that can be torn out and used | |