Definition of Tier 1, Tier 2, 3 teams

What makes a team tier 1? Tier 2? Is it qualifying for big events? Or being on the top 10 of the region?
By this definition is Sentinels currently tier 2?

its all arbitrary

there is no definition but generally people put tier 1 as top 10 teams / the teams in the highest league / teams that make challengers playoffs and teams that actually got a real chance at winning

tier 2 generally is salaried teams (can be an f/a team if they are great) and they are outside of the top 10 / highest league

tier 3 is generally semi-pro unsalaried players or free agent teams

it can also be separated into world wide tiers and regional tiers also, tier 1 world is different to tier 1 brazil for example

a gatekeeper team is one that is very consistent at beating tier 2 teams but also very consistently loses to tier 1 teams

It's about ranking but on a long term, so no SEN is still Tier 1. Teams have kind of stable positions be cause it's often the same teams that play T1 /T2 or T3 events.

tier 1 = all EMEA teams
tier 2 = all NA teams

Tier 3 = sen

Tier 2 = TSM

Tier 1 = OpTic

Tier 17= EMEA