A sentence style characterized by sentences ending in 'da'. It can give an explanatory or somewhat formal/literary tone and is used in descriptions, essays, or some narrative contexts.
学術論文では、ですます体よりだ体（である体）が好まれる場合がある。
In academic papers, the da (dearu) style is sometimes preferred over the desu/masu style.
日記やメモを書くときは、気楽にだ体で書く人も多い。
Many people casually write diaries or notes in the da style.