What is sintering and sinter point?

Sintering is a process of compaction using heat and pressure where the heat is less than the melting temperature.

Whilst I haven't heard of a "sinter point" before, I would assume this is a lowest temperature at which there is a slope change to the amount of compaction by pressure.

Sintering is used for iron oxide (haematite) reduction!!!.
The three solid components are iron oxide, coke(carbon) and limestone (Calcium carbonate).

Before loading into the blast furnace , they are intimately crushed, so that all three solid components are a close as possible, (maximise the surface area).
It is then heated to a point where it becomes like a 'solid honeycomb', in order that the carbon monoxide (hot gas) can move between the particles to react.

Sintering is the process of compacting and forming a solid mass of material by heat and/or pressure without melting it to the point of liquefaction.

What Is Sintering