Means possibly ‘Upward Leaping Flame’ for ‘am’ = up, upwards and ‘lach’ or ‘lhach’= leaping flame

Amlach was the son of Imlach, son of Marach. He was a leader of the Men of Estolad who, along with Bereg of the house of Bëor began to speak out against the Eldar in Middle-earth. They believed the Eldar to be ‘wise but fell’ and they gathered together others who believed the same.

A council was held, and some men spoke out on behalf of the Elves. But amongst them one rose up ‘who seemed to all to be Amlach son of Imlach’ and he spoke fiercely against the Eldar saying, amongst other things, that it was the elves who sought the dominion of Middle-earth.

After the council, Amlach walked among his people and he denied that he had been present at the debate or had said any of the words which he was reported to have spoken. The people were confused and those who remained Elf-friends told them that it was the work of a Dark Lord who indeed existed though they had tried to deny it.

Many still believed that they would not have to fear Morgoth if they would not ally themselves with the Kings of the Eldar who had the quarrel with the Dark Lord. But Amlach repented and felt that he now had a quarrel of his own with Morgoth - and that the quarrel would last until the end of his days. For this reason, he went to the north where he entered the service of Maedhros.
Encyclopedia entry originally written by Nienna-of-the-Valar