<p>I thinked think "raid" was when many monsters spawns some times and "invasion" was when a boss comes to Tibia, but is not true.</p><p></p><p>Looking for a definition on fansites:</p><p>I found in tibia.fandom.com a page about raids, here <a rel="nofollow" href="https://tibia.fandom.com/wiki/Raid">https://tibia.fandom.com/wiki/Raid</a>. In this page we can find Grynch Clan Goblin Invasion and Undead Jester Invasion. So we have raids and invasions used for the same event.</p><p>Looking for a definition on Tibia:</p><p>In the isle of the kings library has a book "Demonic Invasions Paragraph I (Book)" <img alt="" src="https://vignette.wikia.nocookie.net/tibia/images/d/d2/Book_%28Brown_Square%29.gif/revision/latest?cb=20071229163944&path-prefix=en" style="height:32px; width:32px"> that use the word "Invasion" to define when a boss comes to Tibia, but the tibia client has a notify that says "Active raid".</p><p>So, in practice, we have not a difference.</p><p></p><p>Source: <a rel="nofollow" href="https://tibia.fandom.com/">https://tibia.fandom.com/</a></p><p></p>