 unit</code>.</p><p>The initial <i>m</i> marks this as monoidal concatenation rather than the <a href="index.html#val-concat"><code>concat</code></a> function inherited from the underlying <a href="../../Semigroup/module-type-S/index.html"><span>Semigroup</span></a>. Since <a href="index.html#val-mconcat"><code>mconcat</code></a> can use the <a href="index.html#val-unit"><code>unit</code></a> to prime the fold, it can work over a normal list, in contrast to <a href="index.html#val-concat"><code>concat</code