Abarim Publications' online Biblical Hebrew Dictionary
The medieval Masoretes, who worked to preserve what they believed was the proper pronunciation of the Biblical texts, began to make distinctions between words spelled with the letter ש (s). If they thought an occurrence of the ש was pronounced like our letter s, they marked it with a dot to the left: שׂ (sin). And if they thought it had to be pronounced as sh, they marked it with a dot to the right: שׁ (shin).
Words of the form שטה (sth) became subsequently spelled as either שׁטה (shatta) or שׂטה (sata), but from the time that the Bible was written to about a thousand years after, they were indistinguishable.
The feminine noun שטה (shitta) denotes the acacia tree, which is a thorny tree that tends to grow in dry places. Apart from a mentioning in Isaiah 41:19, all occurrences of this noun have to do with the tabernacle and its articles, such as the Ark of the Covenant (Exodus 25:5, Deuteronomy 10:3).
Our noun occurs mostly in the plural form: שטים (shittim) and is probably a loan word from Egyptian, which is significant because Horus was said to have emerged from the acacia tree (Pyramid Text 436, while the acacia was known as the tree in which life and death were enclosed).
One of the characteristics of the acacia is its thorns. It's not specifically mentioned, but Moses burning bush (סנה, seneh; Exodus 3:2) and Christ's crown of thorns may very well have been woven from acacia twigs (Matthew 27:29).
The verb שטה (sata) means to turn away from a righteous life towards an unrighteous one and particularly one that involves extra-marital relations. Our verb occurs only in three paragraphs, namely one which describes an unfaithful woman (Numbers 5:12-29) and one that warns a young man to not associate with a prostitute (Proverbs 7:25). The third instance only talks about an unrighteous lifestyle, but the wording seems to either suggest a context of or else a commentary on unfaithfulness (Proverbs 4:15).
A similar link between a tree and a sideway motion exists in the verb לוז (luz), meaning to turn aside, and the noun לוז (luz), meaning almond tree.
Also note that this verb is similar in form to the root שטן (stn), from whence comes the familiar noun שטן (satan), meaning adversary.