The substance or essence of something — the core reality rather than its outward form.
この会議の実質は予算削減についての議論だった。
The substance of this meeting was a discussion about budget cuts.
見かけよりも実質が大事だ。
Substance is more important than appearance.
彼の説明は長かったが、実質は一言で言える内容だった。
His explanation was long, but the substance could be said in one sentence.
Refers to something substantive or real (e.g. 'real interest rate') — the actual amount or effect rather than the nominal or formal value.
実質金利は名目金利からインフレ率を差し引いて計算する。
The real interest rate is calculated by subtracting the inflation rate from the nominal interest rate.
給与は名目上増えたが、実質ではほとんど変わらない。
Salaries increased nominally, but in real terms they hardly changed.
その制度は見た目は違うが、実質的には同じ効果がある。
The system looks different, but in substance it has the same effect.
Used adverbially to mean 'in effect', 'in practice', or 'essentially' — indicating the true state of affairs.
会員数は50名と発表されたが、実質参加者は30名ほどだった。
They announced 50 members, but in effect only about 30 participated.
彼は形式上は社長だが、実質は会社を動かしているのは副社長だ。
He's president in name, but in practice it's the vice president who runs the company.
この変更で、実質何も変わらないだろう。
This change will essentially change nothing.
In anatomy, '実質' (parenchyma) refers to the tissue of an organ that performs its essential functions (e.g. hepatic parenchyma).
肝臓の実質（肝実質）は代謝や解毒の主要な役割を担っている。
The hepatic parenchyma performs major roles such as metabolism and detoxification.