user3750: What does the v in vin and vout stand for? And is it an instance of a more general naming scheme?

user208: The original Satoshi codebase used a programming style called "Hungarian notation", where variable names are prefixed with letters that indicate the data type they contain.
v in particular stands for "vector". So vin and vout just mean "in vector" and "out vector", and were (and are) the variable names for the inputs and outputs of a transaction.
In UTXOs, that name sort of got inherited, and "vout index" got abbreviated to vout in certain context.

3750: <p>What does the <code>v</code> in <code>vin</code> and <code>vout</code> stand for? And is it an instance of a more general naming scheme?</p>
 208: <p>The original Satoshi codebase used a programming style called &quot;Hungarian notation&quot;, where variable names are prefixed with letters that indicate the data type they contain.</p>
<p><code>v</code> in particular stands for &quot;vector&quot;. So <code>vin</code> and <code>vout</code> just mean &quot;in vector&quot; and &quot;out vector&quot;, and were (and are) the variable names for the inputs and outputs of a transaction.</p>
<p>In UTXOs, that name sort of got inherited, and &quot;vout index&quot; got abbreviated to vout in certain context.</p>
