plack

As an interjection alack

is an expression of sorrow or mourning.

As a noun plack is

sheet, plate (of metal).

As nouns the difference between slack and plack

is that slack is small coal; coal dust while plack is any of various small coins used in Scotland and the Netherlands during the 15th and 16th centuries, having a value in Scotland of four pennies Scots.

As an adjective slack

is lax; not tense; not hard drawn; not firmly extended.

As an adverb slack

is slackly.

As a verb slack

is to slacken.

As nouns the difference between plank and plack

is that plank is a long, broad and thick piece of timber, as opposed to a board which is less thick while plack is sheet, plate (of metal).

As a verb plank

is to cover something with planking.

As a proper noun black

is .

As a noun plack is

sheet, plate (of metal).