Sass maps examples.

SassMeister-input-HTML.html

<div class="box">\o/</div>

SassMeister-input.scss

// ----
// Sass (v3.3.8)
// ----

//********************************************
//
//    MEDIA QUERIES BREAKPOINTS
//
//********************************************
$breakpoints: (
  pequeno:     767px, 
  medio:       992px, 
  grande:      1200px
);

@mixin responde-a($tamanho) {
  @if map-has-key($breakpoints, $tamanho) {
    @media (min-width: #{map-get($breakpoints, $tamanho)}) {
      @content;
    }
  }
  @else {
    @warn "Infelizmente não foi possível encontrar o valor " + #{$tamanho} + " definido em '$breakpoints'.";
  }
}

.elemento {
  width: 300px;
  @include responde-a(pequeno) {
    width: 100%;
  }
}

//********************************************
//
//    CORES
//
//********************************************
$paleta: (
  turquoise:    #1abc9c,
  green-sea:    #16a085,
  esmerald:     #2ecc71,
  nephritis:    #27ae60,
  black:        #303030,
  white:        #ededed
);

@function cor($cor) {
  @if map-has-key($paleta, $cor) {
    @return #{map-get($paleta, $cor)};
  }
  @warn "Cor " + #{$cor} + " não listada em '$paleta' map.";
  @return null;
}

.box {
  display: inline-block;
  padding: 1em;
  background: cor(turquoise);
  color: cor(white);
}

//********************************************
//
//    CAMADAS Z-INDEX
//
//********************************************
$camadas-z: (
  buraco:      -9999,
  padrao:      1,
  dropdown:    3000,
  overlay:     4000,
  modal:       4001
);

@function z($posicao) {
  @if map-has-key($camadas-z, $posicao) {
    @return #{map-get($camadas-z, $posicao)};
  }
  @warn "Posição " + #{$posicao} + " não encontrada em '$camada-z' map.";
  @return null;
}

.box {
  z-index: z(modal);
}

//********************************************
//
//    ICONS CLASS
//
//********************************************
$icones: (
  glass:          "\f000",
  music:          "\f001",
  search:         "\f002",
  envelope-o:     "\f003",
  heart:          "\f004"
);

@each $nome, $icone in $icones {
  .i-#{$nome}:before {
    content: '#{$icone}';
  }
}

SassMeister-output.css

.elemento {
  width: 300px;
}
@media (min-width: 767px) {
  .elemento {
    width: 100%;
  }
}

.box {
  display: inline-block;
  padding: 1em;
  background: #1abc9c;
  color: #ededed;
}

.box {
  z-index: 4001;
}

.i-glass:before {
  content: "\f000";
}

.i-music:before {
  content: "\f001";
}

.i-search:before {
  content: "\f002";
}

.i-envelope-o:before {
  content: "\f003";
}

.i-heart:before {
  content: "\f004";
}

SassMeister-rendered.html

<div class="box">\o/</div>