堆積|たいせきtaiseki[0]heiban (flat)

1. noun, suru verb, transitive verb, intransitive verbaccumulation; pile; heap
2. noun, suru verb, intransitive verb, geologysedimentation

• Synonym集積しゅうせきWrittenWritten/formal prose for scattered things gathering and piling up, as in 「産業集積」 or 「情報の集積」; 「堆積」 stresses layer upon layer and sedimentation.
• Synonym蓄積ちくせきWrittenWritten/formal prose for storing up so the stock grows; knowledge, fatigue, fat, harmful substances all fit, e.g. 「疲労の蓄積」「脂肪の蓄積」; 「堆積」 is about layering and sediment.
• Synonym累積るいせきWrittenWritten/formal prose for building up by repeated addition, as in 「累積赤字」; fits objects and quantities, stressing the running total where 「堆積」 is about piling in layers.
• Synonym山積さんせきWrittenWritten/formal prose for piling up like a mountain, said mostly of problems and work, e.g. 「課題が山積する」; 「堆積」 is mostly for physical matter such as earth and sand.
• Synonym山積みやまづみNeutralNeutral word for things heaped into a small mountain, e.g. 「書類が山積み」, also for having many problems; more everyday and colloquial than 「堆積」.
• Synonym積もるつもるNeutralNeutral verb for snow or dust settling layer by layer, e.g. 「雪が積もる」, also emotions building up; much more common than 「堆積」 in everyday use.
• Synonym積み重なるつみかさなるNeutralNeutral verb for stacking up in layers, also fatigue, experience or repeated occurrences accumulating, e.g. 「疲れが積み重なる」; more colloquial than 「堆積」.
• RelatedたまるNeutralNeutral verb for things collecting or building up, e.g. 「ほこりが溜まる」「ストレスが溜まる」; the most broadly applicable of these words, and not tied to layer-upon-layer piling.
• RelatedやまNeutralNeutral word: basically 'mountain', but also a heap piled high, as in 「ゴミの山」; it names the pile itself, not the process of piling up.
• Related集まるあつまるNeutralNeutral verb for people or things gathering in one place; the most general term, but it covers only coming together, not piling up in layers.
• Related累増るいぞうWrittenWritten/formal prose for continuous increase, as in 「債務の累増」; focuses on a quantity's growing momentum, not on physical piles.
• Related沈殿物ちんでんぶつWrittenWritten/formal prose for solids sunk to the bottom of a liquid, a chemistry/lab term; 「堆積」 usually means geological deposition of earth and sand underwater or on land.
• Related累加るいかWrittenWritten/formal prose for adding the same amount step by step, a maths/calculation term; not used for physical piling or sedimentation.
• Related堆積物たいせきぶつWrittenWritten/formal prose for the material that has settled, a geology term; 「堆積」 covers both the process of piling or settling and the heap it leaves.
• Related積もり積もるつもりつもるNeutralNeutral verb for piling up more and more, typically of grudges, topics or debts, e.g. 「積もり積もった話」; mostly abstract and often emotionally tinged.
• Antonym削減さくげんWrittenAntonym: cutting expenses, staff and the like, e.g. 「経費削減」; opposite of 「堆積」's growing accumulation in that the number goes from many to few.
• Antonym減少げんしょうNeutralAntonym: a decrease in quantity, e.g. 「人口の減少」; the counterpart to 「堆積」's steady piling up and increase.

For everyday build-up, 「溜まる」 and 「積もる」 are the default words. 「堆積」 itself is for matter settling and piling up layer by layer, as in 「土砂が堆積する」. Use 「蓄積」 for knowledge, fatigue or fat building up, and 「山積」 for problems heaped up. For plain gathering choose 「集まる」; for running totals or increases, 「累積」; for the settled material itself, 「堆積物」 or 「沈殿物」. For the opposite movement, use 「減少」 or 「削減」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 高たかく積み重つみかさなること。
2. 風雨ふうう・氷河ひょうがなどにより運はこばれた土砂どしゃが水底みなそこや地表ちひょうにたまること。