The flower behind the golden pendant of Maitreya is called lotus. This is because lotus has a special symbolic meaning in Buddhism. Lotus is regarded as a symbol of purity and perfection in Buddhism. It can emerge from the mud and produce beautiful flowers, which symbolizes that people can transcend secular troubles and get inner purification and liberation. Lotus is often associated with Buddha's teachings and wisdom, which represents Buddha's consciousness and wisdom.

In addition, lotus is regarded as a symbol of auspiciousness and happiness in many cultures. Its blooming symbolizes prosperity and abundance, and its purity and beauty also remind people of positive quality and spiritual realm. Therefore, designing lotus flowers on the back of the gold pendant of Maitreya with a big belly not only embodies the significance of Buddhism, but also conveys wishes for happiness and a better life.

In a word, the flower behind the golden pendant of Maitreya with a big belly is called lotus, which symbolizes purity, perfection, wisdom and happiness. It has special symbolic significance in Buddhism and is loved and respected in many cultures.