What is the difference between Universe and Population? On one hand, the universe contains "all the entities one wishes to consider in a given situation" on the other the population is "a set of similar items or events which is of interest for some question or experiment".
A co-worker said when she learned statistics they used the word universe; when I did we said population. Neither of us had heard of the other word. What if any is the difference?
 A: I just took stats last year.  Population is, as you described, a complete set of elements (persons or objects) that possess some common characteristic defined by the sampling criteria established by the researcher.  
In statistics, Universe is a synonym of Population.  
Source:
population. (n.d.) Collins English Dictionary – Complete and Unabridged, 12th Edition 2014. (1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014). Retrieved October 20 2017 from https://www.thefreedictionary.com/population
Confirming the use of Universe and Population, as synonyms in modern data science: 
https://stats.oecd.org/glossary/detail.asp?ID=2087
A: The term 'universe', while it has a well-established meaning in set theory and other related mathematical fields, in my experience is rarely used in statistics as a synonym of the term 'population'.
Indeed, all classical statistics textbooks, exclusively use the term 'population', usually defined as

entire group of individuals (not necessarily people) about which we
want information.

On the other hand, the 'sample' can be defined to be

A sample is the part of the population from which we actually collect
information. We use a sample to draw conclusions about the entire
population.

Conceptually the two terms mean essentially the same thing, i.e. the set of all possible statistical units, but past statisticians decided to call this set 'population' so we adhere to this convention.
A: The collection of all elements possessing common characteristics that comprise universe is known as the population. A subgroup of the members of population chosen for participation in the study is called sample. The population consists of each and every element of the entire group.
A: Universe is the set all experimental units, from which a sample is to be drawn. Population is the set of all values of the variables to be studied from those experimental units. Thus, a U-sample contains experimental units, whereas a P-sample contains data.
A: The collection of all elements possessing common characteristic that comprise (Univers) is known as the population.
And the subgroup of the member of population chosen for participating in the studybis called (Sample).
A: Universe, population and sample must be understood together. Universe and population can refer to same thing and can be considered as synonym if only the population you use while choosing your samples includes all the members of universe. If you have data for all the members of universe then your population is universe and you are actually sampling from the universe. However, if you have data for only some members of universe then your population is those members of universe only and you are sampling from those members of universe whose data you have access. For instance, let's say you are doing a survey research on 10 million workers in country X. Your universe is all the workers. If you have access to social security number of all the workers where you can draw your sample of 10 thousand workers, then your universe and population are the same. If you have access to social security numbers of only 1 million workers then your universe is 10 million workers, your population is 1 million workers, and your sample is 10 thousand workers.
A: The universe is broad in its nature. The universe in research is the area of your study while the population is the specific characteristics of the universe and the samples are selected units of the population.
