The temperature at which "vapour pressure of the liquid in an open vessel becomes equal to the atmospheric pressure" is called

The boiling point of a liquid is defined as the temperature at which its vapor pressure becomes equal to the external pressure exerted by the surrounding atmosphere [2]. Under these conditions, molecules throughout the bulk of the liquid gain sufficient energy to overcome intermolecular forces and transition into the gaseous state, forming bubbles that rise to the surface. This temperature is highly dependent on ambient pressure; for instance, reducing the surrounding pressure lowers the boiling point, while increasing it—as seen in a pressure cooker—raises the boiling point [1]. At sea level, where atmospheric pressure is 1 atm, water reaches its 'normal boiling point' at 100°C [1]. In contrast, the melting point refers to the temperature at which a solid transitions to a liquid, and 'liquid point' is not a standard scientific term for this phase transition.

Sources

1. [1] https://www.sciencedirect.com/topics/earth-and-planetary-sciences/boiling-point
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 3: Geological Time Scale The Evolution of The Earths Surface > 3. Geological Time Scale – The Evolution of The Earth's Surface > p. 43