Let's compare dictionaries

It is very interesting to compare the definitions of the same word that appear in different dictionaries.
We must choose the definition which fits better with our subject or the thing we are studing.
For example, we can choose the word "archaeology" and these are the definitions:

According to http://www.oxforddictionaries.com/ it is "the study of human history and prehistory through the excavation of sites and the analysis of artefacts and other remains". Its origins are in the "17th century (in the sene "ancient history"): from modern Latin archaeologia, from Greek arkhaiologia "ancient history", from arkhaios "ancient". The current sense dates from the mid 19th century".

Accordind to http://www.merriam-webster.com/ it is "the scientific study of material remains (as fossil relics, artifacts, and monuments) of past human life and activities".

According to http://www.wordreference.com/ it is "the scientific study of ancient peoples and their cultures by analyzing their remaining tools, utensils, and other objects". It is also defined as "the scientific study of historic or prehistoric peoples and their cultures by analysis of their artifacts, inscriptions, monuments, and other such remains, esp. those that have been excavated" and as "the study of man's past by scientific analysis of the material remains of his cultures".

Finally, I've used http://www.learnersdictionary.com/, where it is defined as "a science that deals with past human life and activities by studying the bones, tools,... of ancient people".

Which of these definitions is the closest to the definition we have studied in our lessons?
I prefer those that appear in http://www.wordreference.com/ because archeologist study all the remains of past and current societies in order to how the people lived and live.