"PS." meaning in English

{
  "head_templates": [
    {
      "args": {},
      "expansion": "PS.",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
    {
      "alt_of": [
        {
          "word": "Proto-Slavic"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Linguistics",
          "orig": "en:Linguistics",
          "parents": [
            "Language",
            "Social sciences",
            "Communication",
            "Sciences",
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Abbreviation of Proto-Slavic."
      ],
      "id": "en-PS.-en-name-OruCzwSG",
      "links": [
        [
          "linguistics",
          "linguistics"
        ],
        [
          "Proto-Slavic",
          "Proto-Slavic#English"
        ]
      ],
      "raw_glosses": [
        "(linguistics) Abbreviation of Proto-Slavic."
      ],
      "synonyms": [
        {
          "word": "PSl."
        }
      ],
      "tags": [
        "abbreviation",
        "alt-of"
      ],
      "topics": [
        "human-sciences",
        "linguistics",
        "sciences"
      ]
    }
  ],
  "word": "PS."
}

{
  "head_templates": [
    {
      "args": {},
      "expansion": "PS.",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
    {
      "alt_of": [
        {
          "word": "Proto-Slavic"
        }
      ],
      "categories": [
        "English abbreviations",
        "English entries with incorrect language header",
        "English lemmas",
        "English proper nouns",
        "English terms spelled with .",
        "English uncountable nouns",
        "English words without vowels",
        "en:Linguistics"
      ],
      "glosses": [
        "Abbreviation of Proto-Slavic."
      ],
      "links": [
        [
          "linguistics",
          "linguistics"
        ],
        [
          "Proto-Slavic",
          "Proto-Slavic#English"
        ]
      ],
      "raw_glosses": [
        "(linguistics) Abbreviation of Proto-Slavic."
      ],
      "tags": [
        "abbreviation",
        "alt-of"
      ],
      "topics": [
        "human-sciences",
        "linguistics",
        "sciences"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "PSl."
    }
  ],
  "word": "PS."
}