Apeak is a term used mostly in nautical contexts to describe a boat when it is perpendicular to the water's surface. Other terms that can be used interchangeably with apeak include attop, on end, erect, vertical, upright, and perpendicular. These synonyms are used to convey the same meaning as apeak, which is when an object is standing upright and alone without any external support. These terms are also used in non-nautical contexts to describe when an object is upright and perpendicular to the ground or surface, like a pole or a tree. Regardless of the context, these terms help convey a specific positioning of an object that is important for clear communication and understanding.