Composite volcanic cone is also called strata cone because of the :

A composite volcanic cone is also known as a stratovolcano because it is built from multiple layers, or 'strata', of volcanic material [2]. These volcanoes are characterized by a steep conical profile formed by the accumulation of alternating sheets of hardened lava flows and pyroclastic materials, such as ash, cinders, and volcanic bombs [5]. The layering occurs because these volcanoes experience periodic intervals of both explosive eruptions, which eject pyroclastic debris, and effusive eruptions, which produce viscous andesitic lava [3]. This viscous lava flows slowly and solidifies quickly near the vent, while the subsequent layers of ash and rock fragments from explosive phases settle on top, steadily increasing the volcano's height and creating its distinct stratified internal structure [3]. This stable construction of alternating layers allows stratovolcanoes to reach significant heights compared to other volcanic types [5].

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 11: Volcanism > Composite Type Volcano (Stratovolcano) > p. 140
2. [2] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 3: Volcanism and Earthquakes > Extrusive Landforms > p. 30
3. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 11: Volcanism > Andesitic Or Acidic Or Composite Or Stratovolcanic Lava > p. 139
4. [5] https://pubs.usgs.gov/gip/volc/types.html