阳 is used in: 太阳 (sun), 阳光 (sunshine/sunny personality), 阳台 (balcony). In philosophy: 阴阳. Many Chinese city names contain 阳: 沈阳, 洛阳, 贵阳.
culture
阴阳 is a fundamental concept in Chinese philosophy. 阳 represents the bright, warm, active, masculine principle - the complement to 阴 (dark, cool, passive).
Left 阝 - the standing form of 阜 mound/hill. On the LEFT it always means hill (distinct from right-side 阝 which is 邑 city). As the indexing radical it places 阳 in the terrain family: the sunny south-facing slope is the literal etymology of 阳.
Right 日 - pictograph of the sun with an inner mark. Pairs with the hill radical for the original picture: sun shining on the southern slope. From this image grew the abstract senses - yang energy, the male principle, anything overt. The traditional 陽 had 昜 instead.
