According to the Merriam-Webster Dictionary, the definition of the word 'surrogate' is:
1: one appointed to act in place of another / 2: one that serves as a substitute
So, as one can see, both definitions imply that a surrogate is a woman who acts as a gestational carrier, that is, substitutes the intended mother to bear the pregnancy for her.
Read the full article on: What Is a Surrogate Mother? – Everything You Should Know ( 89).

Andrea Rodrigo
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics.