Moisture/ˈmɔɪstʃər/ Definition 1 of 5Pro Tip 1/2Plant Necessity Understand 'moisture' as essential for gardening, just like sunlight. Check the soil's moisture before watering your plants. Pro Tip 2/2Retaining Water 'Moisture' can imply the ability of something to hold water, like soil or skin. This lotion helps your skin retain its natural moisture.