An excise tax is one levied on specific goods or commodities produced or sold within a country, or on licenses granted for specific activities. Excises are distinguished from customs duties, which are taxes on importation. Excises are inland taxes, whereas customs duties are border taxes.
and is also different than sales tax:
an excise is distinguished from a sales tax or VAT in three ways: (i) an excise typically applies to a narrower range of products; (ii) an excise is typically heavier, accounting for higher fractions (sometimes half or more) of the retail prices of the targeted products; and (iii) an excise is typically specific (so much per unit of measure; e.g. so many cents per gallon), whereas a sales tax or VAT is ad valorem, i.e. proportional to value (a percentage of the price in the case of a sales tax, or of value added in the case of a VAT).
But what really confused me was the name for excise in Hebrew- blo בלו. I thought it was likely a foreign word - perhaps a mispronunciation of one. So I was certainly surprised to find out that the word is actually biblical! It appears, together with other types of taxes, in the Aramaic section of the Book of Ezra (4:13,20; 7:24).
The Daat Mikra explains b'lo there as a type of food tax. In Bava Batra 8a, the gemara identifies blo as a capitation tax (tax per person). Klein, perhaps influenced by the gemara, says the biblical meaning is "poll tax." How it came to mean "excise" in Modern Hebrew is unclear to me (Ben Yehuda does not have an entry for the word at all.)
As far as the etymology is concerned, Klein writes that it is of unknown origin, and the Daat Mikra says it is perhaps from Persian. However, others say that it derives from the Akkadian biltu - "tribute, gift" (from the verb wabalu, "to bring"), which may be related to the Hebrew root יבל meaning "to bear, carry, conduct". This is would be equivalent to the word masa משא, which can mean both "carrying, burden" as well as "tribute, present", and derives from the root נשא, meaning "to bear, carry" as well.
From יבל, we get the word yevul יבול - "produce, yield" (according to Klein, literally "that which is brought in or gathered in") and hovala הובלה - "transport". Klein also mentions a few more words which perhaps also derive from the root יבל:
- mabul מבול - "flood". He quotes Gesenius as saying that it derives from יבל meaning "to flow". Others say it comes from נבל, to destroy.
- yabelet יבלת - "wart". He writes that perhaps it literally means "a running sore".
- yovel יובל - "jubilee". As we've previously discussed, before it meant jubilee, it meant "ram". Klein writes that it probably derives from יבל, and originally meant "leader of the flock, bellwether". (This source seems to directly connect the jubilee with the concept of "gift".)
- tevel תבל - "world". He notes that it is "usually derived from יבל ( = to bear, carry)". But "it is more probably that it derives from Akkadian tabalu (= continent)."