Several parts combine into one character.

貯 is a phonetic-semantic compound: 貝 (cowrie shell / money — the wealth radical) + 宁 (zhù, originally a depiction of a box for stacking things — providing the sound). The composite literally means "money stacked in a box" = savings. The cowrie shell radical 貝 marks 貯 as part of the wealth-vocabulary family. Mainland China simplified to 贮.

Korean reading "jeo." 貯蓄 (jeochuk, savings — formal financial term), 貯金 (jeogeum, "stored money" = savings deposit / piggy bank money), 貯水池 (jeosuji, "stored-water pond" = reservoir — used for both literal water reservoirs and metaphorical "vote banks" in politics), 貯藏 (jeojang, storage / preservation — used for food storage: "kimchi storage").

Mandarin zhù, 4th tone (simplified 贮). Mandarin uses 贮 mainly for non-monetary storage: 贮藏 (zhùcáng, to store), 贮存 (zhùcún, to keep in storage). For "savings" specifically, modern Mandarin prefers 储 (chǔ): 储蓄 (chǔxù, savings), or the colloquial 存钱 (cúnqián, "deposit money / save money"). Same character 貯 across CJK, but Mandarin shifted the everyday vocabulary to a different morpheme — a clean example of how shared script can mask divergent usage.

Japanese on-reading チョ (cho) — 貯金 (chokin, savings deposit — the everyday Japanese word for putting money in a savings account, especially the postal savings system 郵便貯金 yūbin chokin), 貯蓄 (chochiku, savings), 貯水池 (chosuichi, reservoir). Kun-reading たくわえる (takuwaeru, "to store / accumulate / set aside") — 貯える (takuwaeru) — used for storing not just money but also strength, knowledge, supplies. The childhood 貯金箱 (chokinbako, "savings box" = piggy bank) in Japan often takes the form of beckoning cats, ceramic frogs, or the iconic Japanese country bank mascot tanuki figure.

Memory aid: cowrie shells / money (貝) stacked in a box (宁) — savings.