Shin

Shin is the 21st character of the Alephbet and the last to be 'crowned':

This letter carries two different pronunciations depending on the presence and position of a dot above it. Without any dot (as seen in the previous image), it is pronounced 'sh' as in 'shin', with the same applying if the dot appears to the upper right of the letter:

If however the dot appears above the upper left-hand side, it is pronounced as an 's' as in 'sin':

In all these examples, the character is shown with three 'heads'. It is however not unknown for both 'shin' and 'sin' to be written with four heads:

In this case, scholars suggest that the three headed Shin is representative of the Shin pertaining to this world, whereas the four headed Shin is related to the world to come.

Introduction to Reading Hebrew
The first basics
The Hebrew AlephBet
The Letters of the AlephBet
Aleph
Bet (Beyt)
Gimmel
Dalet
Hey
Vav
Zayin
Chet
Tet
Yod
Kaf
Lamed
Mem
Nun
Samekh
Ayin
Pey (Fey)
Tsade (Tsadik)
Qof
Resh
Shin
Tav
The Significance of the Alephbet
The Basics of Hebrew Verbs
The Hebrew Verb Subject
The Hebrew Verb Object
Hebrew Verb Tenses
Hebrew Verb Voices and Moods
Hebrew Verb Participles
The Infinite Verb Version
Hebrew Nouns
Hebrew Noun Constructs
Using Prefixes With Nouns
Hebrew Pronouns
Hebrew Plural Nouns
Hebrew Adjectives
Identifying Hebrew Questions
Adverbs, Prepositions and Conjunctions
Hebrew Reading Conclusion