Definition of "alder"

Have a tree or two the witches particularly like, such as the alder, larch, cypress and hemlock; then, to counteract any possible evil effects, there must be a holly, yew, hazel, elder, mountain ash or juniper.

1940, Rosetta E. Clarkson, Green Enchantments: The Magic Spell of Gardens, The Macmillan Company, page 273

That's what the tiercel was doing when I found him again in the alder.

1967, J. A. Baker, The Peregrine, page 40

Almost immediately, city alders contacted the campaign to negotiate an ordinance.

2004, Stephanie Luce -, Fighting for a Living Wage, page 121

Chicago's mayor Edward Kennelly, the city alders, and many white Chicagoans opposed this siting plan.

2013, Dawn Day Biehler, Pests in the City: Flies, Bedbugs, Cockroaches, and Rats, page 180

After three years as Ward 1 alder, Sarah Eidelson ’12 will leave city government at the end of the year.

2017 September 28, Isabel Bysiewicz, “Eidelson reflects on time as alder”, in Yale Daily News