They are actually interchangeable as they are malleable. Same with the word Conservative. These words don't actually have set definitions. A Liberal used to be a person who espoused enlightenment ideas. Then they became people who espoused light socialism.

The difference between a liberal and a progressive can easily be the difference between two people who both call themselves liberal, or two people who call themselves progressive. Ultimately, when progressivism has worn itself out, they will have a new name. Then people will argue about whether progressive and "new name" are interchangeable ideas.

And Conservatives will just be what liberals used to be...but with religion

I would say I am a little of both. I can also say that I am NOT a conservative. I think we all would be better off if we had a little of all three, but, it would have to be the OLD conservatism. This new stuff, that since Reagan and the "Contract with America", is as radical, politically, as ISIL is religiously.

The reason they are used interchangeably is because over time words are ultimately defined by how people typically use them, language evolves. People tend to forget that words can have multiple applicable definitions too dependent on context. Also many labels have widely applicable self serving definitions arguable for practically everyone. For example one definition of progressive "favoring or promoting change or innovation." after doing a google search of "progressive definition". I'm sure most people of just about every political party is supportive of change and innovation.

It's so nice of you to cherry pick the definitions of Progressives and Liberals so as to paint them in a good light.

You forgot a few things......

These radical Progressives and Liberals support NO RESTRICTION ABORTIONS OF VIABLE LATE TERM BABIES FOR ANY REASON UP TO BIRTH! They are tied to the radical pro abortion groups and feminist groups at the hip.

It's called big money from lobbyist groups.

Over 80% of Americans want restrictions on late term abortions! These Progressives and Liberals are extremists out of touch with America and out of touch with simple humanity towards our most defenseless.

I noticed after your definition of both Progressives and Liberals, you mentioned how they do not have any plans on cutting the debt (and they never will) while they constantly add more free giveaway programs.

You live in LALA LAND! There will NEVER be enough money forced from the working class to pay for all irresponsible people living off the Government. The more you take from the middle class, the larger the welfre roles grow! IT'S A PONSEY SCHEME!

We just got a taste of the most Liberal president handing out free stuff to everyone and look what happened!

Our national debt DOUBLED from all prior Presidents combined.

Our welfare roles are swollen with record numbers of people living off Government.

Our families are broken with fatherless abandoned children being the new norm.

NEWSFLSH, your progressive liberal utopia is a ball and chain around every working mans neck. All these Progressives have managed to do is worsen the state of our families, grown our welfare roles, brought back a racial divide with constant protests in the streets, assasinated cops, and constant division between America.

Here you are trying to paint these sick radical ideologies as the kinder compassionate politics.

Did you just get out of College with this sick brainwashing?

Try looking at facts instead of rhetoric.

Progressives and Liberals are the most intolerant closed minded non inclusive extremists this nation has ever seen, and they are truly killing this nation.

Thank God Trump was elected and just maybe it's not too late to save this great nation from arrogant controlling socialists.

Hillary has used them interchangeably and so have may others; that's why. That makes them, in fact, interchangeable.

What it means is they are for more and more govt solutions to our problems no matter how big the govt already is. They take this position for 2 reason: 1) they lack the IQ to understand how freedom works and, 2) always more welfare is a great way to buy always more votes, and to cripple more and more Americans.