The definition of inflation is too many dollars chasing to few goods.
You can have an increase in prices due to factors other than an increase in the money supply. You can have crop failures, you can have buying competition from developing nations, you can have gov’t regulations that drive up costs.
But for a true inflation you need an increase in the money supply without any growth in the economy. That’s the monetary phenomenon.
In the 1970s regulation and taxes kept the economy from growing- it stagnated- the production possibility frontier curve couldn’t shift to the right- so every time that the Fed tried to gun the economy by increasing the money supply, “stimulating demand”, the only effect was inflation. Stagflation.
Economists such as Paul Craig Roberts suggested that the solution would be to increase supply. Shift the supply curve to the right. That way when you stimulated demand you would get economic growth instead of inflation. Reagan and his team bought into this. So did some Democrat Senators but no one remembers this.
So regulations were dramatically cut (Trump is doing the same), marginal tax rates were cut, investment tax credits were offered, investment write-offs were accelerated, energy production was encouraged. These shifted the supply curve to the right.
Volcker at the Fed all the while had choked off the growth of money and credit and interest rates went through the roof. When demand picked up the economy grew and inflation collapsed. And Reaganomics succeeded in its goal.