From <span class="searchmatch">Mac</span>Diarmid + -ian. <span class="searchmatch">MacDiarmidian</span> (comparative more <span class="searchmatch">MacDiarmidian</span>, superlative most <span class="searchmatch">MacDiarmidian</span>) Of or relating to Hugh <span class="searchmatch">Mac</span>Diarmid (Christopher...