substantially
substantially は英検準1級・英検1級・TOEIC 600レベルの英単語で、「大幅に、著しく、かなり、実質的に、ほぼ」という意味があります。発音記号は /səbˈstænʃəliː/ です。
意味一覧 (3件)
大幅に、著しく、かなり
解説 Definition
変化や差、進み具合などが大きい程度であることを表す副詞。「大幅に」「著しく」「かなり」の意味で、数量の増減、改善、削減、進捗などが目に見えて大きいことを述べるときに使う。文脈によっては「ほぼ」と自然に訳されることもある。
Substantially means to a large degree or by a significant amount. It is often used when talking about clear changes, improvements, reductions, or differences. The word is common in formal writing and reports.
覚え方のコツ Memory Tip
substantially は「大幅に・著しく・かなり」として覚えます。substantial は「中身がある、しっかりした」から「量や程度がはっきり大きい」という感覚につながります。increase substantially, reduce substantially, improve substantially のように、増減・改善・差が目に見えて大きい時に使います。slightly「わずかに」と反対に置くと、変化の大きさがつかみやすくなります。
`Substantially` comes from `substantial` + `-ly`. Connect `substantial` with something large, solid, or clearly important. In phrases like `increase substantially` or `improve substantially`, it means the change is large, not small. It contrasts well with `slightly`.
例文
The project was substantially completed last month.
そのプロジェクトは先月ほぼ完成した。
Sales increased substantially after the redesign.
再設計の後、売上は大幅に伸びた。
The new system substantially reduced processing time.
新しいシステムは処理時間を大幅に短縮した。
実質的に
(意味 2)解説 Definition
見かけや形式ではなく、中身や実際の効果に注目して「実際にはそうだ」と述べるときに使う。法律・契約・説明文など、やや硬い文脈で「本質的には」「事実上」に近い意味になる。
Substantially is used when something is true in its real effect or essential nature, not just in form or appearance. It is also common when a change is large enough to matter clearly, such as when something increases, decreases, or improves by a significant amount. In formal contexts like law, contracts, or explanations, it often means "essentially" or "for practical purposes."
覚え方のコツ Memory Tip
substantially は substantial（かなりの・実質的な）に -ly が付いた形と見れば覚えやすい。まず substantial を軸に「量や程度がしっかり大きい」「中身の上で見てかなり」という感覚を持つ。increase, reduce, improve substantially のように、数字や状況が目に見えて大きく変わる文脈で頻出。slightly「わずかに」と反対に置くと定着しやすい。fairly / somewhat より強いが、dramatically ほど劇的ではない。文脈によっては substantially all で「実質的にほぼ全部」。
Think of substantially as substantial plus -ly. If substantial means "large" or "real in content," then substantially often means "to a clearly important degree" or "in a real, practical sense." It often appears with verbs like increase, reduce, and improve, and it is useful to remember it against slightly, which shows a much smaller change. In phrases like substantially all, it can mean "almost all in practical terms."
例文
The new system substantially reduced the time needed to process orders.
新しいシステムによって、注文処理に必要な時間が実質的に減った。
Although the wording was slightly different, the two contracts were substantially the same.
表現には多少違いがあったが、その2つの契約は実質的に同じだった。
Sales have improved substantially since the company changed its pricing strategy.
会社が価格戦略を変えて以来、売上は実質的に大きく改善した。
ほぼ
(意味 3)解説 Definition
数量・進行・一致の程度が完全ではないが、それに非常に近いことを表す。特に「ほぼ完成」「ほぼ同じ」のように、全体の大部分に当てはまるときによく使う。
Substantially means to a large degree or in a way that is almost complete, even if not fully complete. It is often used when something is very close to finished, very similar to something else, or true for most of the whole. It can also show that a change, increase, or reduction is clearly large and important.
例文
The report is substantially complete.
その報告書はほぼ完成している。
The new plan is substantially the same as the old one.
その新しい計画は以前のものとほぼ同じだ。
Substantially all of the tickets were sold before noon.
チケットは正午前にほぼ全部売れた。
substantially の語源・成り立ち Etymology
substantially は中英語で substantial＋-ly からでき、さらに古フランス語・後期ラテン語 substantialis にさかのぼります。sub-「下に」＋stare「立つ」が核で、「土台として下にある実体」から“見かけでなく中身として、実質的に”の意味になります。関連語は substance, substantial。
Substantially comes from substantial plus -ly, and substantial comes through Old French and Late Latin from substantialis. The deeper root is Latin sub- "under" and stare "to stand," giving the sense of something that stands underneath as a real base or substance. From that, the adverb came to mean "in essence" or "in a major, meaningful way"; compare substance.
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