The "WHT Enhanced Area Velocity Explorer" (WEAVE) is a multi-object survey spectrograph being built for the 4.2-m William Herschel Telescope at the Observatorio del Roque de los Muchachos (Canary Islands). It will cover a two-degree field of view with more than 900 fibres, with both low and high spectroscopic resolutions in the optical bands. I will explain their main instrumental capabilities and expected timeline for the project. The main scientific goals for each of the sub-surveys -both Galactic and extragalactic- will be reviewed. I will focus on the "Stellar, Circumstellar and Interstellar Physics" (SCIP) sub-survey, that plans to cover the northern Milky Way disc obtaining spectra for different type of targets such as OBA stars, young stellar objects, red super giants, Cepheids and interstellar medium. It plans to address questions regarding the relations between star formation, evolution, and the ISM. For the youngest OBA stars, the SCIP survey will complete the kinematics of stars with Gaia astrometry, providing a 6D view of the young tracers of the Galactic disc. It will also study the physics of these stars, and try to solve some long standing questions about their evolution. High Resolution spectra for some specific areas will provide some insight on the metallicities of the stars helping to complete the whole picture.