This is the 14438th most frequent Spanish word.
yacen
"Yacen" means "they lie" (as in lying down or being situated).
In this sentence, 'yacen' means 'lie' and is used to indicate the physical position or arrangement of objects (the books) resting on a surface (the table).
Los libros yacen sobre la mesa.
The books lie on the table.
Here, 'yacen' conveys the idea of people lying down or being positioned in an outdoor setting, compatible with enjoying an activity or a passive interaction with nature.
Yacen bajo las estrellas, disfrutando del cielo nocturno.
They lie under the stars, enjoying the night sky.
In this context, 'yacen' denotes a stationary position, often associated with places or objects that remain undisturbed or abandoned, in this case, graves in a cemetery.