• 盛大せいだい — grand; magnificent
• 繁盛はんじょう — prosperity (of business)
• 盛況せいきょう — prosperous conditions / success
• 全盛ぜんせい — golden age / peak
• 盛もり付つけ — food arrangement
• 盛もり上あがる — to get excited / liven up

盛 combines 皿 (plate) with 成 (to become, complete). Its original image was piling food high on a dish, which extended to prosperity, abundance, and excitement. In compounds, it often reflects success and thriving activity, while in daily life it is used for serving food or lively gatherings.

盛大せいだいな 結婚式けっこんしきが 行おこなわれた。
A grand wedding ceremony was held.

パーティーは 盛もり上あがってきた。
The party is getting lively.