Today, a three-story turret of a castle without a Tenshu as described later is also categorized as a Tenshu, as is a similar Yagura serving as a symbol; they are sometimes collectively called "Tenshu structure."
現在では、後述する天守のない城の三階櫓やそれに準じる象徴的な櫓も天守に分類され、それらを総称して天守建築などということもある。