We're not defining these ourselves, are we?
We've considered a few different definitions of atheist here. One of them is the lack of belief in a god or gods. Four different classes of objects/people can be identified to meet this definition: People who have heard god claims and not found them credible, people who have never heard of gods, infants/pets and other sentient beings incapable of believing in gods, and inanimate objects like rocks.
How many of these classes do we want to refer to when we ask a question such as, "What fraction of people in a given group are atheists?" Obviously not the rocks and pets, and I find no value in including the infants either, so for me, I want to mean members of the first two groups, even though there is almost nobody over the age of eight has never heard of gods, so that second group is very small. For all practical purposes, it's really only the first group that matters when considering such things as the fraction of atheists compared to Christians in America in 2017, for example.
The point is that we prefer words that embody the ideas we find meaningful over those that we don't, and are free to define concepts according to their usefulness. I have no use for a definition of atheist that includes rocks or infants.
I also have no use for definitions such as the one that defines atheists as people who say that there is no god, a definition that excludes more people that have rejected god claims than it includes if so-called weak atheists outnumber strong atheists. What value is there in dividing weak atheists from strong atheists and calling only one group atheists? The few times one has reason to do this, he can add the modifier weak or strong to atheist.
So, my preferred definition is the one that reflects that: those that give a "No" answer to the question of whether they believe in a god or gods. It includes people that might not call themselves atheists, such as weak atheists who call themselves agnostics but not atheists, people who think that they have to actively disbelieve in the existence of gods to use that word, or perhaps have too many negative associations with the word to self-identify as atheists.
I call them atheists even if they don't because they reject god claims, and that is what matters to me in the culture wars. Those people won't be voting for candidates because they thump Bibles. The won't vote for Trump on the hope that he puts an anti-abortion justice on the Supreme Court or put Roy Moore into the Senate. He won't fight to keep In God We Trust on the currency or to get creationism school-led prayer into the public schools.
So, in answer to your question, in my case, yes, I will define the words to meet my needs.