Meaning
A row of bars rising in height from left to right, often inside a square, like the signal indicator on a phone. It stands for mobile reception and connection strength.
It is the go-to symbol for complaining about bad signal, announcing that a café has good internet or explaining why your reply is late: “Up in the mountains, 📶 barely one bar” Some people also use it for a mood or hype level rising. For Wi-Fi specifically, 🛜 is the clearer choice.