〜ことから
From the fact that… (basis for inference, origin of a name)machine translation
FormationVerb / い-adjective in plain form + ことから; な-adjective + な／である + ことから; noun + である + ことから
〜ことから states the GROUNDS for drawing a conclusion: 窓が開いていることから、泥棒は窓から入ったようだ (from the fact that the window is open, it seems the burglar got in through the window). The first clause is something seen or heard; the second is the conclusion inferred from it — which is why the second clause often takes 〜ようだ、〜と考えられる、〜とわかる.
A second, very common meaning: explaining the ORIGIN of a name or custom: 桜が多いことから、「桜の町」と呼ばれている (because there are many cherry trees, it is called "Cherry Blossom Town"). With this meaning the second clause is usually 〜と呼ばれる、〜と言われる、〜という名前がついた.
Compared with plain から for reasons, ことから is more formal, leans toward writing, and always takes the roundabout route "from an observed fact → infer/name." You don't use ことから for everyday personal reasons for your actions — 眠いことから寝ます is wrong; there, plain から・ので as you've always used them is all you need.
Examples
窓が開いていることから、泥棒は窓から入ったようです。
From the fact that the window is open, it seems the burglar got in through the window.
この町は桜が多いことから、「桜の町」と呼ばれています。
Because it has many cherry blossom trees, this town is called "Cherry Blossom Town".
彼女の顔が青いことから、何かあったのだとわかりました。
From how pale her face was, I realized something must have happened.